Profile of urinary phenanthrene metabolites in smokers and non-smokers

Human Urinary Metabolomics as Biomarkers in Tobacco Users: A Systematic Review

Aim

Urine as a biofluid has been rarely used as a diagnostic fluid in oral diseases. The article aims to systematically review the utility of human urinary carcinogen metabolites as an approach for obtaining important information about tobacco and cancer.

Materials and Methods

The following article reviews the use of urine and its metabolites as biomarkers in various lesions of the oral cavity including oral squamous cell carcinoma and as a screening method in evaluating tobacco and its components. A bibliographic comprehensive search was carried out in the main databases: PUBMED, SciELO, Google Scholar, VHL, and LILACS for articles that were published from 1985 to 2020. The inclusion criteria were "urinary metabolites," "oral cancer/HNSCC," "body fluids," "tobacco," and "metabolomics." A total of 55 articles were collected which included laboratory studies, systematic reviews, and literature of urinary metabolites in tobacco users.

Results

Most of the studies carried out show accurate results with high sensitivity of urinary metabolite biomarkers in individuals with tobacco-based habits and lesions caused by them.

Conclusion

The review indicates that urinary metabolite analysis demonstrates its applicability for the diagnosis and prognosis of disease. Urine is a remarkable and useful biofluid for routine testing and provides an excellent resource for the discovery of novel biomarkers, with an advantage over tissue biopsy samples due to the ease and less invasive nature of collection.

Time trend of exposure to secondhand tobacco smoke and polycyclic aromatic hydrocarbons between 1995 and 2019 in Germany - Showcases for successful European legislation

Starting in 2002, regulations and legislative amendments in Germany focused on the non-smoker protection with several measures to reduce exposure to secondhand tobacco smoke (SHS). The present work aimed to evaluate the relationship between polycyclic aromatic hydrocarbons (PAHs) and SHS exposure and to determine to which extent enforced non-smoking regulations and smoking bans affected the exposure of the non-smoking population in Germany since their implementation in the early 2000s until today. For this purpose, cotinine and selected monohydroxylated PAHs (OH-PAHs) were analyzed by means of (UP)LC-MS/MS in 510 24-h-urine samples of the Environmental Specimen Bank collected over a time span of 24 years from 1995 to 2019. Median urinary cotinine levels were found to steadily and significantly decline by 82% from 1995 to 2019. A significant decrease of urinary 3-hydroxybenzo[a]pyrene (19%), 1-OH-pyrene (39%), 1-naphthol (66%), 1- (17%), 2- (25%), and 3-OH-phenanthrene (22%) was also observed throughout the same time span. The decline in urinary levels of cotinine and several OH-PAHs can most likely be attributed to smoking bans and regulations limiting SHS and PAH exposure. This study therefore emphasizes the relevance of human biomonitoring to investigate the exposure of humans to chemicals of concern, assess the effectiveness of regulatory measures, and help policies to enforce provisions to protect public health.

Assessment of the exposure to polycyclic aromatic hydrocarbons in users of various tobacco/nicotine products by suitable urinary biomarkers

Polycyclic aromatic hydrocarbons (PAHs) occur naturally (bitumen and oils) and are formed during all incomplete combustions of organic materials. PAH exposure sources are manifold and include specific workplaces, ambient air, various foodstuffs, tobacco smoke and some medications. At least four members of this class of chemicals have been classified as proven or probable human carcinogens. Assessment of the exposure to PAHs with suitable methods is of importance, particularly in users of new-generation tobacco/nicotine products, which are intended to replace combustible cigarettes (CCs), a major source of non-occupational exposure to PAHs. In a clinical study comprising a period of 74 h under confinement, we investigated the exposure to naphthalene (Nap), fluorene (Flu), phenanthrene (Phe), pyrene (Pyr) and benzo[a]pyrene (BaP) by measuring urinary monohydroxy-PAH (OH-PAH) derived from these parent compounds in habitual users of CCs, electronic cigarettes (ECs), heated tobacco products (HTPs), oral tobacco (OT), and nicotine replacement therapy products (NRTs). Non-users (NU) of any tobacco/nicotine products served as (negative) control group. Smokers exhibited the highest levels for all PAH biomarkers measured, almost all of which were significantly different from the NU and user groups of all other products investigated. CC smokers were the only group which showed a significant relationship between almost all PAH biomarkers and dose markers such as daily consumption, urinary nicotine equivalents (Nequ) and plasma cotinine (CotP). The ratios in urinary OH-PAH between CC and all other groups were dependent on the biomarker and range from < 2 to > 10. These ratios could at least partly be explained by the enzymes involved, their region-selectivity and inducibility by smoking. In conclusion, cigarette smokers (CC) were the only group, which showed product use dependent exposure to PAHs, whereas users of EC, HTP, NRT and OT were not distinguishable from NU of any tobacco/nicotine products.

Polycyclic aromatic hydrocarbons (PAH) in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V)

Polycyclic aromatic hydrocarbons (PAH) mainly originate from incomplete combustion of organic materials and are, among other sources, found in traffic emissions, smoked or barbecued food, leafy vegetables, and tobacco smoke. Some PAH or their metabolites are hazardous for health and classified as carcinogenic, mutagenic, or toxic to reproduction. Urine samples from 3- to 17-year-old children and adolescents living in Germany were analysed for concentrations of metabolites of the PAH fluorene, naphthalene, phenanthrene, and pyrene in the population-representative German Environmental Survey for Children and Adolescents GerES V (2014-2017). PAH metabolites were analysed in urine samples of 516 participants and could be quantified in 88-100% of the samples. Geometric mean concentrations were: 0.785 μg/L (0.688 μg/g_creatinine) for 1-OH-naphthalene, 4.233 μg/L (3.706 μg/g_crea) for 2-OH-naphthalene, 0.139 μg/L (0.122 μg/g_crea) for 1-OH-phenanthrene, 0.085 μg/L (0.075 μg/g_crea) for 2-OH-phenanthrene, 0.131 μg/L (0.115 μg/g_crea) for 3-OH-phenanthrene, 0.045 μg/L (0.040 μg/g_crea) for 4-OH-phenanthrene, 0.058 μg/L (0.050 μg/g_crea) for 9-OH-phenanthrene, 0.511 μg/L (0.448 μg/g_crea) for Σ-OH-phenanthrene, and 0.099 μg/L (0.087 μg/g_crea) for 1-OH-pyrene. Analyses of subgroups revealed higher PAH metabolite concentrations in young children compared to adolescents, and also in residents of former East Germany compared to those living in former West Germany. Increased urinary PAH metabolite concentrations were found in participants using domestic fuel for heating or gas for cooking. Plastic objects were identified as another potential source of exposure. Urinary concentrations of naphthalene and fluorene metabolites were elevated in active smokers and to the same extent in non-smokers exposed to passive smoking. Comparison with previous cycles of GerES revealed a decrease over time and a further decline in the still significant differences in urinary PAH metabolite concentrations of participants living in former East versus West Germany.

Quantitation of phenanthrene dihydrodiols in the urine of smokers and non-smokers by gas chromatography-negative ion chemical ionization-tandem mass spectrometry

Polycyclic aromatic hydrocarbons (PAH) are well-established environmental carcinogens likely to be causative agents for some human cancers. Bay-region diol epoxides are ultimate carcinogenic metabolites of multiple PAH. Dihydrodiols are the important intermediate products of this pathway and can be further oxidized to form diol epoxides. We quantified two dihydrodiol metabolites of phenanthrene (Phe), the simplest PAH with a bay-region, in the 6 h urine of smokers (N = 25) and non-smokers (N = 25) using a newly developed and validated analytical method. After hydrolysis by ß-glucuronidase and sulfatase, and solid phase extraction, the sample was silylated and analyzed by gas chromatography-negative ion chemical ionization-tandem mass spectrometry (GC-NICI-MS/MS). Levels (nmol/6h urine) of Phe-1,2-dihydrodiol (Phe-1,2-D) and Phe-3,4-dihydrodiol (Phe-3,4-D) were 2.04 ± 1.52 and 0.51 ± 0.35 , respectively, in smokers, significantly higher than those in non-smokers (1.35 ± 1.11 of Phe-1,2-D, p < 0.05; 0.27 ± 0.25 of Phe-3,4-D, p < 0.005). Cigarette smoking also influenced the regioselective metabolism of Phe, presenting as a significant difference in the urinary distribution pattern of Phe-1,2-D and Phe-3,4-D between smokers and non-smokers: the ratio Phe-3,4-D: Phe-1,2-D increased from 0.20 in non-smokers to 0.28 in smokers (p < 0.01), which can be explained by the induction of the phenanthrene metabolizing enzymes CYP1A2 and CYP1B1 by cigarette smoke. The method described here is the first example of facile quantitation of an intact human dihydrodiol metabolite of any PAH with three or more aromatic rings and will be applicable in clinical and molecular epidemiology studies of PAH metabolism and cancer susceptibility.

Exposure characterization and estimation of benchmark dose for cancer biomarkers in an occupational cohort of diesel engine testers

Exposure to diesel engine exhaust (DEE) was associated with various adverse health effects including lung cancer. Particle size distribution and profiles of organic compounds in both particle and gas phases of DEE that could provide valuable insights into related health effects were measured in a diesel engine testing workshop. Concentrations of urinary 6 mono-hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) in 137 DEE-exposed workers and 127 non-DEE-exposed workers were determined. Benchmark dose method was applied to estimate lower limit of benchmark dose (BMDL) of urinary OH-PAHs most specific to DEE exposure for previously reported cancer biomarkers. We found that 84.3% of diesel exhaust particles were ultrafine particles. Indeno[123-cd]pyrene and phenanthrene were the most abundant carcinogenic and noncarcinogenic PAHs in the particle phase of DEE, respectively. Principal component analysis demonstrated that urinary hydroxyphenanthrene (OHPhe) had highest loading value on principal component (PC) representative of DEE exposure and lowest loading value on PC representative of smoking status. BMDLs of urinary OHPhe from best-fitting models for cancer biomarkers including micronucleus and 1,N⁶-ethenodeoxyadenosine were 1.08 μg/g creatinine and 2.82 μg/g creatinine, respectively. These results provided basis for understanding DEE exposure induced health effects and potential threshold for regulating DEE levels in an occupational setting.

Quantification of urinary mono-hydroxylated metabolites of polycyclic aromatic hydrocarbons by on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

Human exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). Gas chromatography (GC) has been widely used to separate OH-PAHs before quantification by mass spectrometry in biomonitoring studies. However, because GC requires derivatization, it can be time consuming. We developed an on-line solid phase extraction coupled to isotope dilution-high performance liquid chromatography-tandem mass spectrometry (on-line-SPE-HPLC-MS/MS) method for the quantification in urine of 1-OH-naphthalene, 2-OH-naphthalene, 2-OH-fluorene, 3-OH-fluorene, 1-OH-phenanthrene, the sum of 2-OH and 3-OH-phenanthrene, 4-OH-phenanthrene, and 1-OH-pyrene. The method, which employed a 96-well plate platform and on-line SPE, showed good sensitivity (i.e., limits of detection ranged from 0.007 to 0.09 ng/mL) and used only 100 μL of urine. Accuracy, calculated from the recovery percentage at three spiking levels, varied from 94 to 113 %, depending on the analyte. The inter- and intra-day precision, calculated from 20 repeated measurements of two quality control materials, varied from 5.2 to 16.7 %. Adequate method performance was also confirmed by acceptable recovery (83-102 %) of two NIST standard reference materials (3672 and 3673). This high-throughput on-line-SPE-HPLC-MS/MS method can be applied in large-scale epidemiological studies. Graphical abstract Example LC-MS chromatogram of urinary mono-hydroxylated PAH metabolites.

Urinary Metabolites of Polycyclic Aromatic Hydrocarbons and the Association with Lipid Peroxidation: A Biomarker-Based Study between Los Angeles and Beijing

Air pollution is among the top threats to human health in China. As air toxicants, polycyclic aromatic hydrocarbons (PAHs) could bring significant risks to population; however, the exposure to PAHs in China and its health impact are not fully understood. In 2012, a summer exchange program allowed 10 students to travel from Los Angeles to Beijing and stay there for 10 weeks. Based on the program, this study investigated the difference in urinary concentration of 12 hydroxylated-PAHs (Σ12OH-PAHs) and malondialdehyde (MDA) between the two cities. The median concentration of Σ12OH-PAHs in Beijing (14.1 μg g(-1) creatinine) was significantly higher than that in Los Angeles (5.78 μg g(-1) creatinine), indicating a higher exposure in Beijing. The ratios of homogeneous OH-PAHs (e.g., 1-/2-OH-NAP) changed significantly between the two cities (p < 0.01), which might suggest a potential alteration in metabolism subsequent to exposure. A significant association between Σ12OH-PAHs and MDA (p < 0.01) was observed, with the association varying between the two cities. This study suggests that exposure to PAHs might be linked to metabolism alteration and calls for future studies to investigate the role this possible alteration played in the health effects of PAHs exposure.

Exposure and kinetics of polycyclic aromatic hydrocarbons (PAHs) in cigarette smokers

Our study objectives were (1) to investigate the selectivity of polycyclic aromatic hydrocarbon (PAH) metabolites for tobacco smoke exposure and (2) to determine half-lives of PAH metabolites in smokers. There were 622 participants from the United States (US) and Poland, and of these, 70% were smokers. All subjects provided spot urine samples, and 125 smokers provided blood samples. Urinary PAH metabolite half-lives were determined in 8 smokers. In controlled hospital studies of 18 smokers, the associations between various measures of nicotine intake and urinary excretion of PAH metabolites were investigated. Plasma nicotine was measured by GC. LC-MS/MS was used to measure the plasma levels of cotinine and trans-3'-hydroxycotinine, and urine levels of nicotine and its metabolites, total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and PAH metabolites (2-naphthol, 1-, 2-, and 3-hydroxyfluorenes, 1-, 2-, 3-, and 4-hydroxyphenanthrenes, and 1-hydroxypyrene). Regardless of smoking status, PAH metabolite excretion was higher in Polish subjects than in US subjects (p-values <0.001). 1-Hydroxyfluorene exhibited the greatest difference between smokers and nonsmokers, with a 5-fold difference in Polish subjects and a 25-fold difference in US subjects, followed by 3- and 2-hydroxyfluorenes, 2-naphthol, and 1-hydroxypyrene. The differences for hydroxyphenanthrenes were small or nonsignificant. 1-Hydroxyfluorene had the highest correlation with urine nicotine equivalents (r = 0.77) and urine NNAL (r = 0.64). While the half-lives of PAH metabolites were <10 h in smokers, 1-hydroxyfluorene had the largest ratio of initial to terminal urine concentration (58.4 ± 38.6, mean ± SD) after smoking. Receiver Operating Characteristic (ROC) analysis of PAHs among Polish and US subjects further showed that hydroxyfluorenes are most highly discriminative of smokers from nonsmokers followed by 2-naphthol and 1-hydroxypyrene. In conclusion, hydroxyfluorenes, particularly 1-hydroxyfluorene, and 2-naphthol are more selective of tobacco smoke than 1-hydroxypyrene and hydroxyphenanthrenes. Characterization of hydroxyfluorene and 2-naphthol metabolites in urine may improve the characterization of PAHs from tobacco smoke and related disease risks among smokers and nonsmokers.

Metabolism of [D10]phenanthrene to tetraols in smokers for potential lung cancer susceptibility assessment: comparison of oral and inhalation routes of administration

Polycyclic aromatic hydrocarbons (PAHs) are believed to be among the causative agents for lung cancer in smokers. PAHs require metabolic activation for carcinogenicity. One pathway produces diol epoxides that react with DNA, causing mutations. Because diol epoxides are converted to tetraols, quantitation of tetraols can potentially be used to identify smokers who may be at higher risk for lung cancer. Our approach uses [D(10)]phenanthrene, a labeled version of phenanthrene, a noncarcinogenic PAH structurally analogous to carcinogenic PAH. Although smokers are exposed to PAH by inhalation, oral dosing would be more practical for phenotyping studies. Therefore, we investigated [D(10)]phenanthrene metabolism in smokers after administration by inhalation in cigarette smoke or orally. Sixteen smokers received 10 μg of [D(10)]phenanthrene in a cigarette or orally. Plasma and urine samples were analyzed for [D(10)]r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene ([D(10)]PheT), the major end product of the diol epoxide pathway, by gas chromatography-negative ion chemical ionization-tandem mass spectrometry. The ratios of [D(10)]PheT (oral dosing/inhalation) in 15 smokers were 1.03 ± 0.32 and 1.02 ± 0.35, based on plasma area under the concentration-time curve (0-∞) and total 48-h urinary excretion, respectively. Overall, there was no significant difference in the extent of [D(10)]PheT formation after the two different routes of exposure in smokers. A large interindividual variation in [D(10)]PheT formation was observed. These results demonstrate that the level of [D(10)]PheT in urine after oral dosing of [D(10)]phenanthrene can be used to assess individual capacity of PAH metabolism by the diol epoxide pathway.

Differential exposure biomarker levels among cigarette smokers and smokeless tobacco consumers in the National Health and Nutrition Examination Survey 1999-2008

Assessment of biomarkers is an appropriate way to estimate exposure to cigarette mainstream smoke and smokeless tobacco (SLT) constituents in tobacco consumers. Using the US National Health and Nutrition Examination Survey (NHANES, 1999-2008), biomarkers of volatile organic compounds, halogenated aromatic hydrocarbons (HAHs), polycyclic aromatic hydrocarbons (PAHs), acrylamide, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and metals were evaluated. In general, biomarker levels in SLT consumers were significantly lower than in smokers (excluding NNK and some HAHs) and were not significantly different compared with nonconsumers (excluding NNK and some PAHs). These results provide useful information for science-based risk assessment and regulation of tobacco products.

Preferential glutathione conjugation of a reverse diol epoxide compared to a bay region diol epoxide of phenanthrene in human hepatocytes: relevance to molecular epidemiology studies of glutathione-s-transferase polymorphisms and cancer

Bay region diol epoxides are recognized ultimate carcinogens of polycyclic aromatic hydrocarbons (PAH), and in vitro studies have demonstrated that they can be detoxified by conjugation with glutathione, leading to the widely investigated hypothesis that individuals with low activity forms of glutathione-S-transferases are at higher risk of PAH induced cancer, a hypothesis that has found at most weak support in molecular epidemiology studies. A weakness in this hypothesis was that the mercapturic acids resulting from the conjugation of PAH bay region diol epoxides had never been identified in human urine. We recently analyzed smokers' urine for mercapturic acids derived from phenanthrene, the simplest PAH with a bay region. The only phenanthrene diol epoxide-derived mercapturic acid in smokers' urine was produced from the reverse diol epoxide, anti-phenanthrene-3,4-diol-1,2-epoxide (11), not the bay region diol epoxide, anti-phenanthrene-1,2-diol-3,4-epoxide (10), which does not support the hypothesis noted above. In this study, we extended these results by examining the conjugation of phenanthrene metabolites with glutathione in human hepatocytes. We identified the mercapturic acid N-acetyl-S-(r-4,t-2,3-trihydroxy-1,2,3,4-tetrahydro-c-1-phenanthryl)-L-cysteine (14a), (0.33-35.9 pmol/mL at 10 microM 8, 24 h incubation, N = 10) in all incubations with phenanthrene-3,4-diol (8) and the corresponding diol epoxide 11, but no mercapturic acids were detected in incubations with phenanthrene-1,2-diol (7), and only trace amounts were observed in incubations with the corresponding bay region diol epoxide 10. Taken together with our previous results, these studies clearly demonstrate that glutathione conjugation of a reverse diol epoxide of phenanthrene is favored over conjugation of a bay region diol epoxide. Since reverse diol epoxides of PAH are generally weakly or nonmutagenic/carcinogenic, these results, if generalizable to other PAH, do not support the widely held assumption that glutathione-S-transferases are important in the detoxification of PAH in humans.

A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the determination of phenolic polycyclic aromatic hydrocarbons (OH-PAH) in urine of non-smokers and smokers

Polycyclic aromatic hydrocarbons (PAH) are products of the incomplete combustion of organic materials and, therefore, occur ubiquitously in the environment and also in tobacco smoke. Since some PAH have been classified as carcinogens, it is important to have access to suitable analytical methods for biomarkers of exposure to this class of compounds. Past experience has shown that measuring a profile of PAH metabolites is more informative than metabolites of a single PAH. Assessment of environmental and smoking-related exposure levels requires analytical methods with high sensitivity and specificity. In addition, these methods should be fast enough to allow high throughput. With these pre-conditions in mind, we developed and validated a high-performance liquid chromatographic method with tandem mass spectrometric detection (LC-MS/MS) for the determination of phenolic metabolites of naphthalene, fluorene, phenanthrene and pyrene in urine of smokers and non-smokers. Sample work-up comprised enzymatic hydrolysis of urinary conjugates and solid-phase extraction on C18 cartridges. The method showed good specificity, sensitivity, and accuracy for the intended purpose and was also sufficiently rapid with a sample throughput of about 350 per week. Application to urine samples of 100 smokers and 50 non-smokers showed significant differences between both groups for all measured PAH metabolites, and strong correlations with markers of daily smoke exposure in smoker urine. Urinary levels were in good agreement with previously reported data using different methodologies. In conclusion, the developed LC-MS/MS method is suitable for the quantification of phenolic PAH metabolites of naphthalene, fluorene, phenanthrene, and pyrene in smoker and non-smoker urine.

Analysis of phenanthrene and benzo[a]pyrene tetraol enantiomers in human urine: relevance to the bay region diol epoxide hypothesis of benzo[a]pyrene carcinogenesis and to biomarker studies

One widely accepted metabolic activation pathway of the prototypic carcinogenic polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (BaP) proceeds through the "bay region diol epoxide" BaP-(7R,8S)-diol-(9S,10R)-epoxide (2). However, few studies have addressed the analysis of human urinary metabolites of BaP, which result from this pathway. Phenanthrene (Phe) is structurally related to BaP, but human exposure to Phe is far greater, and its metabolites can be readily detected in urine. Thus, Phe metabolites have been proposed as biomarkers of PAH exposure and metabolic activation. Phe-tetraols in particular could be biomarkers of the diol epoxide pathway. While BaP-tetraols and Phe-tetraols have been previously quantified in human urine, no published studies have determined their enantiomeric composition. This is important because different enantiomers would result from the bay region diol epoxide and "reverse" diol epoxide pathways, the latter being associated with weak mutagenicity and carcinogenicity. We addressed this problem using chiral HPLC to separate the enantiomers of BaP-7,8,9,10-tetraol and Phe-1,2,3,4-tetraol. Urine samples from smokers were subjected to solid-phase extraction, chiral HPLC, and GC-NICI-MS/MS analysis for silylated Phe-1,2,3,4-tetraols. The results demonstrated that >96% of Phe-1,2,3,4-tetraol in smokers' urine was Phe-(1S,2R,3S,4R)-tetraol (12), resulting from the "reverse" diol epoxide pathway, whereas less than 4% resulted from the "bay region diol epoxide" pathway of Phe metabolism. Urine from creosote workers was similarly analyzed for BaP-7,8,9,10-tetraol enantiomers. In contrast to the results of the Phe-tetraol analyses, 78% of BaP-7,8,9,10-tetraol in these human urine samples was BaP-(7R,8S,9R,10S)-tetraol (3) resulting from the "bay region diol epoxide" pathway of BaP metabolism. These results provide further support for the bay region diol epoxide pathway of BaP metabolism in humans and demonstrate differences in BaP and Phe metabolism, which may be important when considering Phe-tetraols as biomarkers of PAH metabolic activation.

Urinary hydroxylated metabolites of polycyclic aromatic hydrocarbons as biomarkers of exposure in asphalt workers

BACKGROUND

Fumes and vapours released during laying of hot asphalt mix have been recognised as a major source of exposure for asphalt workers.

OBJECTIVES

We investigated the relationships between inhalation exposure to asphalt emissions and urinary biomarkers of polycyclic aromatic hydrocarbons (PAHs) in asphalt workers (AW, n=75) and in ground construction workers (CW, n=37).

METHODS

Total polyaromatic compounds (PAC) and 15 priority PAHs in inhaled air were measured by personal sampling. Hydroxylated PAH metabolites (OH-PAHs) (2-naphthol, 2-hydroxyfluorene, 3-hydroxyphenanthrene, 1-hydroxypyrene, 6-hydroxychrysene and 3-hydroxybenzo[a]pyrene) were determined in urine spot samples collected in three different times during the work week.

RESULTS

Median vapour-phase PAC (5.5 microg m(-3)), PAHs (<or=50 ng m(-3)) and OH-PAHs (0.08-1.11 microg l(-1)) were significantly higher in AW than in CW, except in the cases of air naphthalene and 2-naphthol. Airborne levels of particle-phase contaminants were similar in the two groups and much lower than vapour-phase levels; metabolites of particulate PAHs were never found in quantifiable amounts. An appreciable increase in OH-PAH levels during the work day and work week was found in AW; median levels for 2-hydroxyfluorene, 3-hydroxyphenanthrene and 1-hydroxypyrene were, respectively, 0.29, 0.08 and 0.18 at baseline; 0.50, 0.18 and 0.29, pre-shift; 1.11, 0.44 and 0.44 microg l(-1), post-shift. Each OH-PAH exhibited a characteristic profile of increase, reflecting differences in half-lives of the parent compounds. In non-smoking subjects, positive correlations were found between vapour-phase PAC or PAHs and OH-PAHs both in pre- and post-shift samples (0.34 <or= r<or=69). Smokers exhibited 2-5-fold higher OH-PAHs than non-smokers, at any time and at both workplaces.

CONCLUSIONS

Our results suggest that OH-PAHs are useful biomarkers for monitoring exposure to asphalt emissions. The work-related exposure to PAC and PAHs was low in all AW, but urinary metabolites reflected exposure satisfactorily.

Analysis of phenanthrene diol epoxide mercapturic acid detoxification products in human urine: relevance to molecular epidemiology studies of glutathione S-transferase polymorphisms

Many studies have investigated the effects of glutathione S-transferase (GST) polymorphisms on cancer incidence in people exposed to carcinogenic polycyclic aromatic hydrocarbons (PAHs). The basis for this is that the carcinogenic bay region diol epoxide metabolites of several PAH are detoxified by GSTs in in vitro studies. However, there are no reports in the literature on the identification in urine of the mercapturic acid metabolites that would result from this process in humans. We addressed this by developing a method for quantitation in human urine of mercapturic acids which would be formed from angular ring diol epoxides of phenanthrene (Phe), the simplest PAH with a bay region, and a common environmental pollutant. We prepared standard mercapturic acids by reactions of syn- or anti-Phe-1,2-diol-3,4-epoxide and syn- or anti-Phe-3,4-diol-1,2-epoxide with N-acetylcysteine. Analysis of human urine conclusively demonstrated that the only detectable mercapturic acid of this type--N-acetyl-S-(r-4,t-2,3-trihydroxy-1,2,3,4-tetrahydro-c/t-1-phenanthryl)-L-cysteine (anti-PheDE-1-NAC)--was derived from the 'reverse diol epoxide', anti-Phe-3,4-diol-1,2-epoxide, and not from the bay region diol epoxides, syn- or anti-Phe-1,2-diol-3,4-epoxide. Levels of anti-PheDE-1-NAC in the urine of 36 smokers were (mean +/- SD) 728 +/- 859 fmol/ml urine. The results of this study provide the first evidence for a mercapturic acid of a PAH diol epoxide in human urine, but it was not derived from a bay region diol epoxide as molecular epidemiologic studies have presumed, but rather from a reverse diol epoxide, representative of metabolites with little if any carcinogenic activity. These results demonstrate the need for integration of genotyping and phenotyping information in molecular epidemiology studies.

New biomarkers of occupational exposure to polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAH) are metabolized in a complex manner. Although biological activity is associated with diol-epoxide formation, phenolic metabolites have predominantly been used in human biomonitoring. In this study monohydroxylated and new metabolites were characterized as biomarkers for occupational PAH exposure. In 97 male workers, personal exposure to 16 airborne PAH compounds was measured during shift. In postshift urine, 1-hydroxypyrene and 1,6- and 1,8-dihydroxypyrene (1-OHP, DiOHP) were determined as metabolites of pyrene (P), and the sum of 1-, 2-, 3-, 4-, and 9-hydroxyphenanthrenes (OHPHE), and PHE-dihydrodiols (PHED) as metabolites of phenanthrene (PHE). The referent group comprised 21 nonsmoking construction workers. Median (interquartile range) shift concentrations of airborne P and PHE were 1.46 (0.62-4.05 microg/m(3)) and 10.9 (3.69-23.77 microg/m(3)), respectively. The corresponding parameters were 3.86 (2.08-7.44) microg/g creatinine (crn) for 1-OHP, 0.66 (0.17-1.65) microg/g crn for DiOHP, 11.44 (5.21-34.76) microg/g crn for OHPHE, and 12.28 (3.3-97.76) microg/g crn for PHED in PAH-exposed workers. The median levels of 1-OHP and OHPHE were 0.09 (0.08-0.17 microg/m(3)) and 0.59 (0.45-1.39 microg/m(3)), respectively, in the referents. PHE correlated significantly with OHPHE and PHED, and P with 1-OHP but not with DiOHP. Under a doubling of PHE, OHPHE increased by a factor of 1.56 and PHED by 1.57. With a doubling of P, 1-OHP rose by 1.31 and DiOHP by 1.27. P is predominantly metabolized into 1-OHP, whereas PHE is metabolized equally into OHPHE and PHED. Thus metabolites of PHE were found as reliable biomarkers for PAH exposure.

Biological monitoring of occupational exposure to polycyclic aromatic hydrocarbons (PAH) by determination of monohydroxylated metabolites of phenanthrene and pyrene in urine

OBJECTIVES

The aim of our study was to assess individual polycyclic aromatic hydrocarbon (PAH) exposure of workers coming from three different industrial branches by several parameters of external and internal exposure. By analysing the relationships between those markers the suitability of individual parameters [e.g. monohydroxylated phenanthrene (Phe) metabolites] for exposure surveillance should be evaluated.

METHODS

The total study population consisted of 255 male workers (age: 19-62, mean: 39.61 years), who were employed in coke production (n=40), production of graphite electrodes and special carbon products (92), or production of refractory materials (123), respectively. For each worker external PAH exposure was determined by personal air sampling of 16 PAH, including Phe, pyrene (Pyr) and benzo[a]pyrene (BaP). For determination of internal PAH exposure the excretion of the PAH metabolites 1-, 2 + 9-, 3-, 4-hydroxyphenanthrene and 1-hydroxypyrene was measured in post-shift urine samples of all workers.

RESULTS

In the total study population median total PAH exposure and exposure to BaP were 30.62 and 0.27 microg/m(3), respectively. A calculation of PAH profiles resulted in substantial branch-related variations with Phe being a major component. Considering all branches the median excretions of 1-hydroxypyrene and hydroxyphenanthrenes (sum) were 6.68 and 11.22 microg/g creatinine. A correlation analysis yielded a good correlation between total ambient PAH exposure and excretion of hydroxyphenanthrenes in urine (r=0.662; P<0.01), but no significant correlation between Phe metabolites and the carcinogenic BaP. For 1-hydroxypyrene and BaP a weak but significant association was found (r=0.235; P<0.01).

CONCLUSIONS

Considering the results of the correlation analysis hydroxyphenanthrenes in urine should reflect an uptake of lowly condensed volatile PAH rather than an incorporation of highly condensed PAH like BaP which should be reflected better by 1-hydroxypyrene. Therefore, the determination of hydroxyphenanthrenes in addition to the well-established marker 1-hydroxypyrene could offer some further information about the exposure situation at a particular work place.

Dose-Response Modeling of Occupational Exposure to Polycyclic Aromatic Hydrocarbons with Biomarkers of Exposure and Effect

In regulatory toxicology, the dose-response relationship between occupational exposure and biomarkers is of importance in setting threshold values. We analyzed the relationships between occupational exposure to polycyclic aromatic hydrocarbons (PAH) and various biomarkers of internal exposure and DNA damage with data from 284 highly exposed male workers. Personal exposure to phenanthrene and other PAHs was measured during shift and correlated with the sum of 1-, 2+9-, 3-, and 4-hydroxyphenanthrenes in post-shift urine. PAHs and hydroxyphenanthrenes were associated with DNA damage assessed in WBC as 8-oxo-7,8-dihydro-2'-deoxyguanosine/10(6) dGuo and strand breaks by Comet assay as Olive tail moment. Hydroxyphenanthrenes correlated with phenanthrene (Spearman r(s) = 0.70; P < 0.0001). No correlations could be found between strand breaks and exposure (r(s) = 0.01, P < 0.0001 for PAHs; r(s) = -0.03, P = 0.68 for hydroxyphenanthrenes). Correlations with 8-oxo-7,8-dihydro-2'-deoxyguanosine/10(6) dGuo were weakly negative (r(s) = -0.22, P = 0.004 for PAHs) or flat (r(s) = -0.08, P = 0.31 for hydroxyphenanthrenes). Linear splines were applied to assess the relationships between the log-transformed variables. All regression models were adjusted for smoking and type of industry. For hydroxyphenanthrenes, 51.7% of the variance could be explained by phenanthrene and other predictors. Up to 0.77 microg/m(3) phenanthrene, no association could be found with hydroxyphenanthrenes. Above that point, hydroxyphenanthrenes increased by a factor of 1.47 under a doubling of phenanthrene exposure (slope, 0.56; 95% confidence interval, 0.47-0.64). Hydroxyphenanthrenes may be recommended as biomarker of occupational PAH exposure, whereas biomarkers of DNA damage in blood did not show a dose-response relation to PAH exposure.

Determination of phenolic metabolites of polycyclic aromatic hydrocarbons in human urine as their pentafluorobenzyl ether derivatives using liquid chromatography-tandem mass spectrometry

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants, and a number of them are carcinogenic. One approach for measuring exposure to them is to determine the concentrations of metabolites in urine. The pyrene metabolite 1-hydroxypyrene has been used as a biomarker for exposure in numerous studies. However, determination of exposure to several PAHs may be advantageous, since the relative amounts may vary depending upon the exposure source. We developed a liquid chromatography-tandem mass spectrometry method for the determination of phenolic metabolites of naphthalene, fluorene, phenanthrene, and pyrene in human urine. Following enzymatic cleavage of the glucuronide and sulfate conjugates, the phenolic metabolites are extracted from urine and converted to pentafluorobenzyl ethers. These derivatives greatly enhance the sensitivity of detection by atmospheric pressure chemical ionization in the negative ion mode. Lower limits of quantitation range from 0.01 to 0.5 ng/mL. Stable isotope-labeled internal standards were synthesized or obtained commercially. Data on urinary excretion of several PAH metabolites in urine of smokers and nonsmokers are presented.

3-Hydroxybenzo[a]pyrene in the urine of smokers and non-smokers

The people studied were male volunteers without occupational and dietary exposure to PAH: 27 smokers (10 cigarettes or more) and 27 non-smokers matched for age and socio-professional category. For each person, all the 24h voided urine samples were reassembled in a single sample. 1-Hydroxypyrene (1-OHPy) and 3-hydroxybenzo[a]pyrene (3-OHBaP) were then determined by automated column-switching high-performance liquid chromatography. Urinary 1-OHPy ranged from 0.041 to 0.530 micromol/molCreatinine (arithmetic mean 0.144, median 0.115) for smokers and from 0.01 to 0.148 mmol/molCreatinine (arithmetic mean 0.044, median 0.032) for non-smokers. These values are close to those of some other studies. Urinary 3-OHBaP ranged from <0.01 to 0.084 nmol/molCreatinine (arithmetic mean 0.030, median 0.023) for smokers and from <0.01 to 0.045 nmol/molCreatinine (arithmetic mean 0.014, median 0.011) for non-smokers. Considering more particularly the urinary 3-OHBaP values, the influence of smoking could be important among workers exposed to low levels of BaP (<100 ng/m(3)) and the concentrations for smokers were equivalent to most of the preshift values of exposed workers. The dietary BaP intake was slightly lower than the BaP intake for an average smoker. From the present study, temporary basic reference levels may be proposed for urinary 3-OHBaP.

Assessment of soil remediation workers' exposure to polycyclic aromatic hydrocarbons (PAH): biomonitoring of naphthols, phenanthrols, and 1-hydroxypyrene in urine

Urinalysis of multiple polycyclic aromatic hydrocarbons (PAH) biomarkers has been applied to assess the exposure of soil remediation workers on a former creosote wood impregnation site polluted with creosote oil. The uptake of PAHs was measured in preshift, end-of-shift, evening, and next preshift specimens (n=33) of nine volunteers with diverse tasks, using sensitive HPLC-FD methods. The ranges of biomarker concentrations in urine (nmol/l) were: 1-naphthol (14-159), 2-naphthol (9-166), 1- plus 2-naphthol (35-269), 1-hydroxyphenanthrene (OHPhe) (6-56), 2- plus 3-OHPhe (6-70), 4-OHPhe (1-6), 9-OHPhe (1-7), the sum of phenanthrols (15-135), and 1-hydroxypyrene, OHP (2.2-67). Eight of nine workers had OHP levels higher than the Finnish biological limit value for non-occupationally exposed persons (3nmol/l). A linear correlation was observed between 1- and 2-naphthol (r=0.90). The biomarker OHP correlated well in urine both with the major (1-OHPhe, r=0.96; 2- plus 3-OHPhe, r=0.84) and the minor phenanthrene metabolites (4-OHPhe, r=0.77; 9-OHPhe, r=0.68), and with the sum of all phenanthrols (r=0.94), but not so well with the sum of naphthols (r=0.66, p<0.001). The smokers had 2.9-, 2.2-, and 4.8-fold higher average concentrations of naphthols, phenanthrols, and OHP, respectively, than the non-smokers. The PAH biomarker data (concentrations and diurnal excretion profiles) showed significant work-related exposure in both non-smoking and smoking subjects. The average exposure levels were clearly higher than those we have measured for instance in asphalt paving workers. The workers' exposure should be assessed by biological monitoring, because at this type of outdoor work the dermal and pulmonary uptake of PAHs are both likely. Adequate measures for preventing, particularly, dermal absorption are of crucial importance for reducing the workers' risk of exposure to carcinogens on soil remediation sites.

Analysis of Phenanthrols in Human Urine by Gas Chromatography-Mass Spectrometry: Potential Use in Carcinogen Metabolite Phenotyping

Phenanthrene is the simplest polycyclic aromatic hydrocarbon (PAH) containing a bay region, a feature closely associated with carcinogenicity. We have proposed that measurement of phenanthrene metabolites in human urine could be used to identify interindividual differences in metabolic activation and detoxification of PAH, and that these differences may be related to cancer susceptibility in smokers and other exposed individuals. Previously, we reported a method for quantitation of r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (trans, anti-PheT) in human urine. trans, anti-PheT is the ultimate product of the diol epoxide metabolic activation pathway of phenanthrene. In this study, we have extended our carcinogen metabolite phenotyping approach by developing a method for quantitation of phenanthrols in human urine. PAH phenols such as phenanthrols are considered as detoxification products. After treatment of the urine by β-glucuronidase and arylsulfatase, a fraction enriched in phenanthrols was prepared by partitioning and solid phase extraction. The phenanthrols were silylated and analyzed by gas chromatography-positive ion chemical ionization-mass spectrometry with selected ion monitoring. [ring-13C6]3-phenanthrol was used as an internal standard. Accurate and reproducible quantitation of four phenanthrols, 1-phenanthrol (1-HOPhe), 2-HOPhe, 3-HOPhe, and 4-HOPhe, was readily achieved. In smokers, mean levels of 1-HOPhe (0.96 ± 1.2 pmol/mg creatinine) and 3-HOPhe (0.82 ± 0.62 pmol/mg creatinine) were greater than those of 2-HOPhe (0.47 ± 0.29 pmol/mg creatinine), and 4-HOPhe (0.11 ± 0.07 pmol/mg creatinine). There were no significant differences between the levels of any of the phenanthrols in smokers and nonsmokers. Total levels of the quantified phenanthrols were highly correlated with those of 3-HOPhe. Ratios of phenanthrene metabolites representing activation and detoxification were calculated as trans, anti-PheT divided by 3-HOPhe. There was a 7.5-fold spread of ratios in smokers, and a 12.3-fold spread in nonsmokers, suggesting that this may be a useful parameter for distinguishing individual metabolic responses to PAH exposure.

Air concentrations and urinary metabolites of polycyclic aromatic hydrocarbons among paving and remixing workers

The exposure of paving workers to polycyclic aromatic hydrocarbons (PAH) during stone mastic asphalt (SMA) paving and remixing was evaluated. The effects on the workers' PAH exposure were also evaluated during the use of an industrial by-product, coal fly ash (CFA), instead of limestone as the filler in the SMA. The PAH exposure was measured by personal air sampling and by analysing the levels of urinary naphthols, phenanthrols and 1-hydroxypyrene (1-OHP) in the workers' pre- and post-shift urine samples. The respiratory PAH exposure of the paving workers (geometric mean (GM) 5.7 microg m(-3)) was about ten-fold that of the traffic controllers (GM 0.43 microg m(-3)). The levels of PAH metabolites were significantly higher (p < 0.05) in the post-shift urine samples than in the pre-shift urine samples, and the levels of metabolites in the post-shift urine of paving workers were significantly higher than in that of the controls (p < 0.01). Urinary 1-naphthol correlated well with the airborne concentrations of the two- to three-ring PAHs (r = 0.544, p = 0.003) and naphthalene (r = 0.655, p < 0.001), when non-smoking paving workers were tested. A good correlation was observed between urinary 1-OHP and the airborne concentrations of the four- to six-ring PAHs (r = 0.524, p = 0.003) as well as total PAHs (r = 0.575, p = 0.001). The concentrations of 1-OHP and phenanthrols in the urine of the pavers were significantly higher (p < 0.01) during remixing than during SMA paving. The CFA in the asphalt had no effect on the airborne PAH exposure or on the concentrations of the PAH metabolites in the paving workers' urine.

Urinary hydroxy-metabolites of naphthalene, phenanthrene and pyrene as markers of exposure to diesel exhaust

OBJECTIVE

The objective of this study was to assess the exposure of bus-garage and waste-collection workers to polycyclic aromatic hydrocarbons (PAHs) derived from diesel exhaust by the measurement of levels of seven urinary PAH metabolites: 2-naphthol, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, 1+9-hydroxyphenanthrene, 4-hydroxyphenanthrene and 1-hydroxypyrene.

SUBJECTS AND METHODS

One urine sample from each of 46 control persons, and one pre-shift and two post-shift spot urine samples from 32 exposed workers were obtained in winter and in summer. The metabolites were analysed after enzymatic hydrolysis by high performance liquid chromatography (HPLC) with fluorescence detection.

RESULTS

The sum of seven PAH metabolites (mean 3.94 +/- 3.40 and 5.60 +/- 6.37 micromol/mol creatinine in winter and summer, respectively) was higher [P=0.01, degrees of freedom (df) =61.2 and P=0.01, df=67.6 in winter and summer, respectively] in the exposed group than in the control group (mean 3.18 +/- 3.99 and 3.03 +/- 2.01 micromol/mol creatinine in winter and summer, respectively). The mean concentrations of 2-naphthol among exposed and controls ranged between 3.34 and 4.85 micromol/mol creatinine and 2.51 and 2.58 micromol/mol creatinine, respectively (P<0.01 in winter, P<0.03 in summer). The mean level of the hydroxyphenanthrenes in the samples of exposed workers was between 0.40 and 0.70 micromol/mol creatinine and in the control samples 0.40-0.60 micromol/mol creatinine. The concentration of 1-hydroxypyrene was higher among exposed workers in both pre-shift and post-shift samples (mean 0.10-0.15 micromol/mol creatinine) than in control group (mean 0.05-0.06 micromol/mol creatinine) in winter (P=0.002, df=78) and in summer (P<0.001, df=68).

CONCLUSIONS

The urinary hydroxy-metabolites of naphthalene, phenanthrene and pyrene showed low exposure to diesel-derived PAHs; however, it was higher in exposed workers than in control group. Urinary PAH monohydroxy-metabolites measured in this study did not correlate with the PAHs in the air samples, reported earlier, in 2002 and 2003.

Simultaneous determination of urinary 1- and 2-naphthols, 3- and 9-phenanthrols, and 1-pyrenol in coke oven workers

A method was developed for simultaneous quantification of urinary 1- and 2-naphthols, 3- and 9-phenanthrols and 1-pyrenol using gas chromatography with mass spectrometry (GC-MS). This method was applied to urine samples from coke oven workers (n=28) and controls (n=22) from Northern China. Geometric mean levels of urinary 1-naphthol (58.8 microg l(-1)), 2-naphthol (34.1 microg l(-1)), 3-phenanthrol (7.35 microg l(-1)), 9-phenanthrol (1.28 microg l(-1)) and 1-pyrenol (25.4 microg l(-1)) were significantly higher among coke oven workers than controls. All the substances tested were highest among top-of-oven workers, who had 15-fold higher 1-naphthol, eight-fold higher 2-naphthol and 20-fold higher 1-pyrenol levels compared with controls. Using multiple linear regression models, 72.5% of the variation in 1- and 2-naphthol and 82.8% of the variation in 1-pyrenol were explained by the concentration of naphthalene or pyrene in the urine, the work category and the smoking intensity. Cigarette consumption significantly contributed to levels of urinary 1-pyrenol and naphthols, particularly 2-naphthol. A negative relationship between work category and the ratio of naphthols/1-pyrenol was observed among smokers. Our results suggest that urinary naphthols and phenanthrols reflect polycyclic aromatic hydrocarbon (PAH) exposure as well as the widely used 1-pyrenol, and that interactions between cigarette smoking and PAH exposure result in different patterns of metabolism for individual PAHs.

German Environmental Survey 1998 (GerES III): environmental pollutants in the urine of the German population

The German Environmental Survey (GerES) is a cross-sectional probability study to determine the exposure of the general population to environmental contaminants. The study was repeated for the third time in 1998 (GerES III). Again, a stratified random procedure was used to select the study population taking into account the parameters gender, age, community size and place of residence (West- or East-Germany). A total of 4822 persons between 18 and 69 years of age from 120 localities participated in GerES III. Human biomonitoring comprised the determination of arsenic, cadmium, mercury, metabolites of polycyclic aromatic hydrocarbons (PAH), pentachlorophenol (PCP), other chlorophenols, precious metals (gold, platinum, iridium), nicotine, and cotinine in urine.

Biomonitoring of polycyclic aromatic hydrocarbons in human urine

Measurement of polycyclic aromatic hydrocarbons (PAH) metabolites in human urine is the method of choice to determine occupational and/or environmental exposure of an individual to PAH, in particular, when multiple routes of exposure have to be taken into account. Requirements for methods of biomonitoring PAH metabolites in urine are presented. Studies using 1-hydroxypyrene or phenanthrene metabolites including its phenols and dihydrodiols are summarized. The role of these PAH metabolites as established biomarkers and also more recent developments of PAH biomonitoring are discussed.

Human urinary carcinogen metabolites: biomarkers for investigating tobacco and cancer

Measurement of human urinary carcinogen metabolites is a practical approach for obtaining important information about tobacco and cancer. This review presents currently available methods and evaluates their utility. Carcinogens and their metabolites and related compounds that have been quantified in the urine of smokers or non-smokers exposed to environmental tobacco smoke (ETS) include trans,trans-muconic acid (tt-MA) and S-phenylmercapturic acid (metabolites of benzene), 1- and 2-naphthol, hydroxyphenanthrenes and phenanthrene dihydrodiols, 1-hydroxypyrene (1-HOP), metabolites of benzo[a]pyrene, aromatic amines and heterocyclic aromatic amines, N-nitrosoproline, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (NNAL and NNAL-Gluc), 8-oxodeoxyguanosine, thioethers, mercapturic acids, and alkyladenines. Nitrosamines and their metabolites have also been quantified in the urine of smokeless tobacco users. The utility of these assays to provide information about carcinogen dose, delineation of exposed vs. non-exposed individuals, and carcinogen metabolism in humans is discussed. NNAL and NNAL-Gluc are exceptionally useful biomarkers because they are derived from a carcinogen- 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)- that is specific to tobacco products. The NNAL assay has high sensitivity and specificity, which are particularly important for studies on ETS exposure. Other useful assays that have been widely applied involve quantitation of 1-HOP and tt-MA. Urinary carcinogen metabolite biomarkers will be critical components of future studies on tobacco and human cancer, particularly with respect to new tobacco products and strategies for harm reduction, the role of metabolic polymorphisms in cancer, and further evaluation of human carcinogen exposure from ETS.

Biomonitoring of polycyclic aromatic compounds in the urine of mining workers occupationally exposed to diesel exhaust

Diesel exhaust is considered a probable human carcinogen by the IARC. Biomonitoring of workers occupationally exposed to diesel exhaust was performed to determine their internal burden of diesel associated aromatic compounds. Personal air sampling also allowed to determine the exposure of the miners at their work place towards several polycyclic aromatic hydrocarbons (PAH) and nitro-arenes, the latter of which are thought to be specific constituents of diesel exhaust. For biomonitoring the urine of 18 underground salt miners was collected during and after their shift for 24-hours. half of the 18 miners were smokers. The urinary levels of 1-hydroxypyrene and hydroxylated phenanthrene metabolites were determined as biomarkers of PAH exposure, whereas urinary levels of some aromatic amines were chosen to monitor exposure towards specific nitro-arenes from diesel exhaust like 1-nitropyrene and 3-nitrobenzanthrone and to monitor the human burden by these compounds from inhaled cigarette smoke. Non-smoking workers exposed to diesel exhaust excrete an average level of about 4 micrograms phenanthrene metabolites, whereas the urinary levels in smokers were up to 3-fold higher. In summary the results indicate that (i) diesel exposure led to an increase of PAH metabolism in the workers examined, most probably by an induction of cytochrome P450 (ii) smokers could be identified in accordance with earlier studies by their increased ratio of phenanthrene metabolites derived from 1,2- and 3,4-oxidation and their higher amounts of excreted 1-naphthylamine, and (iii) the excreted amounts of aromatic amines found as metabolites of the nitro-arenes were about 5- to 10-fold higher as one might expect from the levels determined by personal air sampling at the workplace of the individuals.

Monitoring polycyclic aromatic hydrocarbon metabolites in human urine: extraction and purification with a sol-gel glass immunosorbent

A new, rapid method for selective extraction of hydroxylated polycyclic aromatic hydrocarbons metabolites (OH-PAHs) in human urine was developed using an immunosorbent of anti-pyrene antibodies which were encapsulated in a sol-gel glass (SGG) matrix. Resulting chromatograms after immunoextraction of urine samples and HPLC analysis of the extracts were free from matrix interferences. The LODs for the determination of OH-PAHs in these difficult samples were in the low-ppt range (1-16 ng/L). In addition to its high selectivity, the immunosorbent proved to be robust and reusable. Obtained recoveries in spiked urine samples ranged from 83 to 107% for the hydroxyphenanthrene and hydroxypyrene compounds under investigation, while recovery for 3-hydroxybenzo[a]pyrene was only 45-62%. In a biomonitoring study, the SGG immunosorbent was successfully used for trace-level analysis of OH-PAHs in 20 human urine samples. Results were compared to data obtained by an independent reference analysis method and revealed good correlation between both methods.

Occurrence of polycyclic aromatic hydrocarbons in sewage sludge and their contribution to its toxicity in the toxalert 100 bioassay

The contribution of polycyclic aromatic hydrocarbons (PAH) present in sewage sludge samples to toxicity was investigated. Chemical analysis using gas chromatography mass spectrometry (GC-MS) and the ToxAlert 100 bioassay, based on the inhibition to Vibrio fischeri, were applied to sludge extracts after purification by column chromatography. The levels of the 16 US EPA PAH analyzed in the sewage sludge samples varied from 17 to 2,030 microg kg(-1). In all samples examined phenanthrene was the most prominent compound. The toxicity data obtained by ToxAlert 100 can be explained by the levels and composition of the different PAH in sewage sludge samples. The present approach can contribute to evaluate the toxicity of sewage sludge.

Detection of carcinogenic aromatic amines in the urine of non-smokers

Smoking is thought to be one of the most important anthropogenic risk factors involved in the development of urinary bladder cancer in humans. Tobacco smoke contains a complex mixture of chemicals including potent carcinogens such as aromatic amines. In the present study the amounts of several freebase aromatic amines including the potent carcinogens 2-aminonaphthalene and 4-aminobiphenyl have been analyzed in the urine of 48 German urban living smokers and non-smokers. The results indicate that (i) both groups excrete the identical set of four aromatic amines; (ii) smokers excrete approximately twice the total amount of these amines, but similar amounts of 2-aminonaphthalene and 4-aminobiphenyl are found in non-smokers; and (iii) the excreted aromatic amines are decomposed in the urine within a few hours thus, explaining why aromatic amines are difficult to detect in this matrix. Their decomposition could be prevented by adding small amounts of p-toluidine to the freshly collected urine. Unlike smokers the origin of aromatic amines detected in the urine of non-smokers is at present unknown. Based on the cotinine levels found in the urine of non-smokers environmental tobacco smoke can be excluded as a major source of aromatic amines. In addition, neither diesel exhaust-related nitroarenes nor the corresponding amino-derivatives, to which they may be metabolically converted, were found. The detected urinary levels of aromatic amines arising from sources other than tobacco smoke or diesel exhaust may play a role in the bladder cancer etiology of non-smokers.