Genotoxic risk assessment in white blood cells of occupationally exposed workers before and after alteration of the polycyclic aromatic hydrocarbon (PAH) profile in the production material: comparison with PAH air and urinary metabolite levels

Production of a specific monoclonal antibody for 1-naphthol based on novel hapten strategy and development of an easy-to-use ELISA in urine samples

1-naphthol (1-NAP) is the main metabolite of pesticide carbaryl and naphthalene, and is also a genotoxic and carcinogenic intermediate in the synthesis of organic compound, dyes, pigment and pharmaceutical industry. In this work, two novel haptens were designed and synthesized for developing a competitive indirect enzyme-linked immunosorbent assay (ciELISA) method for 1-NAP in urine samples. The assay showed a limit of detection of 2.21 ng/mL and working range from 4.02 ng/mL to 31.25 ng/mL for 1-NAP in optimized working buffer. The matrix effect of samples was eliminated via 15-fold dilution of optimized working buffer. Good average recoveries (102.4%-123.4%) with a coefficient of variation from 11.7% to 14.7% was obtained for spiked urine samples. Subsequent instrument verification test showed good correlation between the results of ciELISA and high-performance liquid chromatography. The developed ciELISA is a high-throughput tool to monitor 1-NAP in urine, which can provide technical support for the establishment of biological exposure level for the exposure to carbaryl, naphthalene and other related pollutants.

Association of PAHs and BTEX exposure with lung function and respiratory symptoms among a nonoccupational population near the coal chemical industry in Northern China

Emissions (particularly aromatic compounds) from coal industries and biomass fuels combustion lead to high health risks for neighboring residents. To investigate the association of polycyclic aromatic hydrocarbons (PAHs) and benzene, toluene, ethylbenzene and 1,2-dimethylbenzene (BTEX) exposure with lung function and respiratory symptoms among adults and children near the coal-chemical industry in Northern China, adults and children from a county dotted with coal chemical industry were chosen as subjects for investigation (investigated area, IR). The control group consisted of adults and children from an agricultural county (control area, CR). The environmental and urinary PAH and BTEX levels of adults and children were determined by isotope dilution liquid chromatography coupled with tandem mass spectrometry. The Mann-Whitney U test and multivariate linear regression models were used to analyze the relationship between pollutant exposure and the respiratory system. The results showed that in an ambient environment, levels of PAHs and BTEX in the IR were significantly higher than those in the CR. Particularly, the concentration profiles for air samples were IR > CR and indoor > outdoor. Both for adults and children, the geometric (GM) concentrations of urinary PAHs and BTEX from the IR were significantly higher than those measured in the CR. Additionally, the urinary PAH exposure level profiles of smokers were higher than those of nonsmokers, indicating that indoor air and smoking were both important nonoccupational exposure sources. The decline of the forced expiratory in the first second (FEV₁, %) and the forced expiratory middle flow rate (FEF_25%) in children were associated with increasing urinary PAH metabolite levels (p < 0.05). The increase in urinary 1-OHN, 3-OHPhe, 4-OHPhe and 1-OHP levels could be linked to a decrease in FEV1 (r = -0.179, p < 0.05) and FEF_25% with the coefficient of -0.166, -0.201 and -0.175 (p < 0.05), respectively. Medical examinations and lung function tests indicated that residents in the IR had higher occurrences of chest inflammation or declining lung function than residents in the CR. Moreover, exposure to PAHs and BTEX could decrease child lung function, though decreased lung function was not observed in adults. Both urinary monitoring and lung function data showed that children were more sensitive to PAH and BTEX exposure than adults.

Comparative toxicity of selected PAHs in rainbow trout hepatocytes: genotoxicity, oxidative stress and cytotoxicity

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in aquatic ecosystems, which may have potentially toxic effects on organisms. In this study occurrence of DNA strand breaks, oxidative stress, and cytotoxicity were investigated in rainbow trout hepatocytes following in vitro exposure for 24 h to four PAHs (0.01-10 µM): naphthalene, fluoranthene, pyrene, and benzo[a]pyrene (B[a]P). The exposed hepatocytes were analyzed for DNA strand breaks using the comet assay and for antioxidant status by measuring intracellular glutathione (GSH) content using the fluorescent probe mBCl. The cytotoxicity of PAHs was assessed using the fluorescent probe CFDA-AM. The results showed that fluoranthene, pyrene, and B[a]P were genotoxic at all exposure concentrations, whereas naphthalene was genotoxic at concentrations ≥0.1 µM. All treatments reduced the intracellular concentrations of GSH for all four PAHs, except 10 µM of B[a]P, suggesting that some level of oxidative stress was present. The cytotoxic effect was observed for naphthalene at concentrations ≥0.1 µM and pyrene at all exposure concentrations, whereas fluoranthene and B[a]P were not cytotoxic at the tested concentrations. The study shows that low-molecular-weight PAHs may cause DNA strand breaks as high-molecular-weight PAHs do in fish tissue. In addition, two- to five-ring PAHs can induce oxidative stress and cytotoxicity.

Linking mobile source-PAHs and biological effects in traffic police officers and drivers in Rawalpindi (Pakistan)

The aim of this study was to evaluate the effect of traffic related polycyclic aromatic hydrocarbons (PAHs) on blood parameters of subjects, including traffic police officers (TP), drivers (DR) and control subjects (CN) with presumably different levels of exposure. We quantified the urinary 1-hydroxypyrene (1-OHPyr), α-naphthol and β-naphthol (α- and β-naph) as biomarkers of exposure to PAHs in relation with biomarkers of effect (Hb, MCV, PCV, PLT, RBCs), biomarkers of inflammation/infection (CRP, WBCs), oxidative stress (SOD) and oxidative DNA damage i.e. 8-hydroxy-2-deoxyguanosine (8-OHdG). Results showed that mean 1-OHPyr, α-naph and β-naph concentrations were significantly higher in TPs (0.98, 1.55, and 1.9µmolmol-Cr(-1), respectively, p<0.05) than CNs (0.7, 0.6; 0.67µmolmol-Cr(-1), respectively, P<0.05). Furthermore, WBC and CRP were found in higher concentrations in TPs than CNs (7.04×10(3)µL(-1) and 0.95mgL(-1) vs. 5.1×10(3)µL(-1) and 0.54mgL(-1), respectively). The urinary 8-OHdG level, a biomarker of oxidative DNA damage, was higher in TPs than both CN and DR subjects (48ngmg-Cr(-1), 24ngmg-Cr(-1) and 33ngmg-Cr(-1), respectively). Self-reported health assessment indicates that, on the basis of daily time spent in the middle of heavy traffic, TPs and DRs more frequently suffered from adverse head and respiratory symptoms. The PCA analysis evidenced the impact of traffic pollution on exposure biomarkers and DNA damage. The study suggests that traffic pollution may be associated with important health risk, in particular on the respiratory system, not only for workers exposed to traffic exhausts but also for general public. Finally, vehicular air pollution in the city of Rawalpindi should be a high-priority concern for the Pakistan Government that needs to be addressed.

Carcinogenicity of ambient air pollution: use of biomarkers, lessons learnt and future directions

The association between ambient air pollution (AAP) exposure and lung cancer risk has been investigated in prospective studies and the results are generally consistent, indicating that long-term exposure to air pollution can cause lung cancer. Biomarkers can enhance research on the health effects of air pollution by improving exposure assessment, increasing the understanding of mechanisms, and enabling the investigation of individual susceptibility. In this review, we assess DNA adducts as biomarkers of exposure to AAP and early biological effect, and DNA methylation as biomarker of early biological change and discuss critical issues arising from their incorporation in AAP health impact evaluations, such as confounding, individual susceptibilities, timing, intensity and duration of exposure, and investigated tissue. DNA adducts and DNA methylation are treated as paradigms. However, the lessons, learned from their use in the examination of AAP carcinogenicity, can be applied to investigations of other biomarkers involved in AAP carcinogenicity.

Fast Screening of Polycyclic Aromatic Hydrocarbons using Trapped Ion Mobility Spectrometry - Mass Spectrometry

In the present paper, we showed the advantages of trapped ion mobility spectrometry coupled too mass spectrometry (TIMS-MS) combined with theoretical calculations for fast identification (millisecond timescale) of polycyclic aromatic hydrocarbons (PAH) compounds from complex mixtures. Accurate PAH collision cross sections (CCS, in nitrogen as a bath gas) are reported for the most commonly encountered PAH compounds and the ability to separate PAH geometric isomers is shown for three isobaric pairs with mobility resolution exceeding 150 (3-5 times higher than conventional IMS devices). Theoretical candidate structures (optimized at the DFT/B3LYP level) are proposed for the most commonly encountered PAH compounds showing good agreement with the experimental CCS values (<5%). The potential of TIMS-MS for the separation and identification of PAH compounds from complex mixtures without the need of lengthy pre-separation steps is illustrated for the case of a complex soil mixture.

Biological monitoring of environmental exposure to polycyclic aromatic hydrocarbons in subjects living in the area of recycling electronic garbage, in Southern China

The study was undertaken to evaluate the environmental exposure to polycyclic aromatic hydrocarbons in subjects living in the area of recycling electronic garbage in Southern China and research the influence of environment smoke tobacco (EST) to people through active and passive smoking. Urinary concentrations of 2-hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, and 1-hydroxypyrene were determined in 141 randomly selected voluntary residents aged 13 to 81 years in two polycyclic aromatic hydrocarbon (PAH)-exposed groups, two control groups, and an EST research group. The concentrations of 2-hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, and 1-hydroxypyrene in PAH-exposed groups are significantly higher (p<0.05) than those of control groups. Mean value of 1-hydroxypyrene in the residents living in the area of recycling electronic garbage (1.1 μmol/mol creatinine) is a little higher than those of iron foundry workers, automobile repair workers, and firefighters. Mean value of 2-hydroxynaphthalene (11.3 μmol/mol creatinine) is much higher than that of shipyard and aircraft maintenance and much lower than some occupational exposure, such as coking batteries, sorting department, and distillation department in coking plant. Some metabolites of PAHs (PAHm) are significantly elevated through active and passive smoking, while the influence of EST to other PAHm is not statistically significant. 2-Hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, and 1-hydroxypyrene in the urine of smokers are, respectively, 3.9, 1.9, 1.4, and 1.9 times to those of nonsmokers. In nonsmokers, passive smokers excreted 1.1, 1.5, 1.9, and 1.5 times of 2-hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, and 1-hydroxypyrene compared to nonpassive smokers.

Urinary naphthol metabolites and chromosomal aberrations in 5-year-old children

BACKGROUND

Exposure to naphthalene, an International Agency for Research on Cancer (IARC)-classified possible carcinogen and polycyclic aromatic hydrocarbon (PAH), is widespread, though resulting health effects are poorly understood. Metabolites of naphthalene, 1- and 2-naphthol, are measurable in urine and are biomarkers of personal exposure. Chromosomal aberrations, including translocations, are established markers of cancer risk and a biodosimeter of clastogenic exposures. Although prenatal (maternal) PAH exposure predicts chromosomal aberrations in cord blood, few studies have examined chromosomal aberrations in school-age children and none has examined their association with metabolites of specific PAHs.

METHODS

Using Whole Chromosome Paint Fluorescent in situ Hybridization, we documented chromosomal aberrations including translocations, in 113 five-year-old urban minority children and examined their association with concurrent concentrations of PAH metabolites measured in urine.

RESULTS

We report that in lymphocytes, the occurrence and frequency of chromosomal aberrations including translocations are associated with levels of urinary 1- and 2-naphthol. When doubling the levels of urinary naphthols, gender-adjusted OR for chromosomal aberrations are 1.63 [95% confidence interval (CI), 1.21-2.19] and 1.44 (95% CI, 1.02-2.04) for 1- and 2-naphthol, respectively; and for translocations OR = 1.55 (95% CI, 1.11-2.17) and 1.92 (95% CI, 1.20-3.08) for 1- and 2-naphthol, respectively.

CONCLUSION

Our results show that markers of exposure to naphthalene in children are associated with translocations in a dose-related manner, and that naphthalene may be a clastogen.

IMPACT

Indoor exposure to elevated levels of naphthalene is prevalent in large regions of the world. This study is the first to present an association between a marker of naphthalene exposure and a precarcinogenic effect in humans.

Oxidative damage in foundry workers occupationally co-exposed to PAHs and metals

Occupational exposure to polycyclic aromatic hydrocarbons (PAHs) has been reported in foundries. A higher risk for DNA damage or oxidative damage lesions was also found in occupationally PAH-exposed groups. The aim of this study was to assess PAH exposure by urinary excretion of 1-hydroxypyrene (1-OHP), a biological exposure marker. Furthermore, we aimed to evaluate the oxidative damage of foundry workers with different job tasks and the association between 1-OHP, metal exposure and oxidative damage in foundry workers exposed to pervasive carcinogens. A higher concentration of 1-OHP was found in the exposed group (0.322+/-0.289 microg/g creatinine) relative to the control group (0.178+/-0.289 microg/g creatinine) (p<0.05). Moreover, higher levels of 1-OHP were found in workers involved in manufacturing processes (0.346 microg/g creatinine) compared to administrative workers (0.018 microg/g creatinine). A positive correlation was identified between levels of 1-OHP and 8-hydroxydeoxyguanosine (8-OH-dG), DNA strand breakage and malondialdehyde (MDA) in all study subjects. However, when foundry workers were considered based on their specific job categories, a similar trend for 1-OHP and three oxidative damage markers was only found for DNA strand breakage, but not for 8-OH-dG or MDA. Other factors such as furnace equipment, PAH types, and job categories may contribute to different PAH emissions. The study also suggested that co-exposure to metal and PAHs, and smoking status in foundry industries may also cause the oxidative damage in foundry workers.

PM2.5 constituents and oxidative DNA damage in humans

Previous studies suggested that certain constituents of ambient PM2.5 can induce or increase oxidative stress in biological systems. The present study is designed to examine whether exposure to traffic generated particles increases the burden of oxidative stress in humans and to identify specific PM2.5 constituents responsible for pollution-induced oxidative stress. We recruited two nonsmoking security guards who worked at a university campus gate by a heavily trafficked road. Pre- and post-workshift spot urines were collected on each of the 29 days of measurement. Concentrations of PM2.5 mass and 126 chemical species were measured at the worksite and a campus background site simultaneously. Urine samples were analyzed for 8-hydroxy-2'-deoxyguanosine (8-OHdG). Factor analysis and linear mixed-effects regression models were used in statistical analyses. Three clusters of PM2.5 species were identified, including PAHs, metals, and polar organic compounds. Urinary concentrations of 8-OHdG increased by > 3 times following an eight-hour workshift in participants. Pre-workshift urinary concentrations of 8-OHdG were associated with PM2.5 concentrations at the background site. Post-workshift 8-OHdG concentrations were significantly and positively associated with PM2.5 mass, PAHs, and metals, but not polar organic species, measured at the worksite. Our findings provide direct evidence in humans that PM compositions are important in increasing oxidative stress burdens. Our results support that PAHs and metals are biologically active constituents of PM2.5 with regards to the induction of oxidative DNA damages in the human body.

Antaxia-telangiectasia mutated gene polymorphisms and susceptibility to chromosomal damage among polycyclic aromatic hydrocarbons exposed workers

The aim was to explore the relationship between the ataxia-telangiectasia mutated (ATM) gene polymorphisms and susceptibility to cytokinesis-block micronucleus among workers exposed to polycyclic aromatic hydrocarbons (PAH). Blood and urine samples of 140 PAH-exposed workers and 66 non-PAH-exposed workers were collected. Seven tagging single nucleotide polymorphisms in ATM gene were selected by pariwise r(2) method and minor allele frequency cutoff of 0.05 from Chinese genotype data in HapMap project. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze the polymorphisms of ATM rs600931, rs652311, rs227060, rs227292, rs624366, rs189037 and rs228589. The results showed that ATM rs600931 AG and AG+AA genotypes exhibited significantly higher cytokinesis-block micronucleus (CBMN) frequency (11.14+/-6.91 per thousand and 10.57+/-6.82 per thousand) than did the GG genotype (7.66+/-5.69 per thousand, P=0.015 and 0.038, respectively). The subjects with rs189037 GA and GA+AA genotypes exhibited significantly higher CBMN frequency (10.99+/-6.90 per thousand and 10.51+/-6.76 per thousand) than that of the GG genotype (7.72+/-5.82 per thousand, P=0.018 and 0.035, respectively). The PAH-exposed workers with rs624366 GC and GC+CC genotypes exhibited significantly higher CBMN frequency (11.34+/-6.74 per thousand and 10.73+/-6.62 per thousand) than did the GG genotype (7.61+/-6.07 per thousand, P=0.001 and 0.003, respectively). rs227092 GT genotype exhibited significantly higher CBMN frequency (10.78+/-6.60 per thousand) than did the GG genotype (7.91+/-6.30 per thousand, P=0.025) among the PAH-exposed workers. The haplotype pairs GGGGTGC/AAACATT exhibited significantly higher CBMN frequency (12.05+/-7.40 per thousand) than did the GGGGTGC/GGGGTGC (7.51+/-6.19 per thousand, P=0.007) among the PAH-exposed group. In conclusion, it is suggested that the polymorphisms of ATM were associated with the CBMN frequencies among PAH-exposed workers.

8-hydroxy-2' -deoxyguanosine (8-OHdG): A critical biomarker of oxidative stress and carcinogenesis

There is extensive experimental evidence that oxidative damage permanently occurs to lipids of cellular membranes, proteins, and DNA. In nuclear and mitochondrial DNA, 8-hydroxy-2' -deoxyguanosine (8-OHdG) or 8-oxo-7,8-dihydro-2' -deoxyguanosine (8-oxodG) is one of the predominant forms of free radical-induced oxidative lesions, and has therefore been widely used as a biomarker for oxidative stress and carcinogenesis. Studies showed that urinary 8-OHdG is a good biomarker for risk assessment of various cancers and degenerative diseases. The most widely used method of quantitative analysis is high-performance liquid chromatography (HPLC) with electrochemical detection (EC), gas chromatography-mass spectrometry (GC-MS), and HPLC tandem mass spectrometry. In order to resolve the methodological problems encountered in measuring quantitatively 8-OHdG, the European Standards Committee for Oxidative DNA Damage was set up in 1997 to resolve the artifactual oxidation problems during the procedures of isolation and purification of oxidative DNA products. The biomarker 8-OHdG or 8-oxodG has been a pivotal marker for measuring the effect of endogenous oxidative damage to DNA and as a factor of initiation and promotion of carcinogenesis. The biomarker has been used to estimate the DNA damage in humans after exposure to cancer-causing agents, such as tobacco smoke, asbestos fibers, heavy metals, and polycyclic aromatic hydrocarbons. In recent years, 8-OHdG has been used widely in many studies not only as a biomarker for the measurement of endogenous oxidative DNA damage but also as a risk factor for many diseases including cancer.

Effect of tobacco compounds on gene expression profiles in human epithelial cells

This study was carried out to investigate the effects of the tobacco compounds (TC), nicotine, B(a)P, and 2-naphthylamine, on gene expression profiles in a human epithelial cells (A549). We treated A549 with the TC and analyzed gene expression using microarray and real-time PCR (RTP). Gene expression varied according to the TC used. By microarray, we found that apoptosis-related genes such as apoptosis-associated tyrosine kinase, interleukin 10 receptor beta, caspase 1 and DNA fragmentation factor beta subunit (40kDa) were down-regulated in TC-treated A549 cells. RTP showed significant increases in the expression of Ahr, Arnt, CYP1A1, and CYP1B1 in TC-treated A549 cells. From these results, we suggest that tobacco compounds can influence apoptosis, inflammation, immunity, and the cell cycle in A549 cells. Also, our study demonstrates that a microarray-based genomic survey is a suitable high-throughput approach for the evaluation of gene expression and for the characterization of TC-induced toxicity.

Validation of biomarkers for the study of environmental carcinogens: a review

There is a need for validation of biomarkers. Our aim is to review published work on the validation of selected biomarkers: bulky DNA adducts, N-nitroso compounds, 1-hydroxypyrene, and oxidative damage to DNA. A systematic literature search in PubMed was performed. Information on the variability and reliability of the laboratory tests used for biomarkers measurements was collected. For the evaluation of the evidence on validation we referred to the ACCE criteria. Little is known about intraindividual variation of DNA adduct measurements, but measurements have a good repeatability irrespective of the technique used for their identification; reproducibility improved after the correction for a laboratory factor. A high-sensitivity method is available for the measurement of 1-hydroxypyrene in urine. There is consensus on validation of biomarkers of oxidative damage DNA based on the comet assay and chromatographic measurement in blood while urinary measurements by chromatographic assays are well validated, and ELISA-based assays appear to lack specificity. Immunoassays for the quantification of adducts of N-nitroso compounds are useful for large epidemiological studies, given their sensitivity, the small amount of DNA required and their potential for rapid and high-throughput analysis.

Seasonal variability of oxidative stress markers in city bus drivers. Part I. Oxidative damage to DNA

We investigated the seasonal variability of 8-oxodeoxyguanosine (8-oxodG), a marker of oxidative damage to DNA, in urine of 50 bus drivers and 50 controls in Prague, Czech Republic, in three seasons with different levels of air pollution: winter 2005, summer 2006 and winter 2006. The exposure to environmental pollutants (carcinogenic polycyclic aromatic hydrocarbons, c-PAHs, particulate matter (PM), and volatile organic compounds (VOC)) was monitored by personal and/or stationary monitors. For the analysis of 8-oxodG levels, the ELISA technique was used. Bus drivers were exposed to significantly higher levels of c-PAHs in winter 2006, while in the other two seasons the exposure of controls was unexpectedly higher than that of bus drivers. We did not see any difference in VOC exposure between both groups in summer 2006 and in winter 2006; VOC were not monitored in winter 2005. 8-OxodG levels were higher in bus drivers than in controls in all seasons. The median levels of 8-oxodG (nmol/mmol creatinine) in bus drivers vs. controls were as follows: winter 2005: 7.79 vs. 6.12 (p=0.01); summer 2006: 6.91 vs. 5.11 (p<0.01); winter 2006: 5.73 vs. 3.94 (p<0.001). Multivariate logistic regression analysis identified PM2.5 and PM10 levels, measured by stationary monitors during a 3-day period before urine collection, as the only factors significantly affecting 8-oxodG levels, while the levels of c-PAHs had no significant influence.

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.

Human biomonitoring: State of the art

Human biomonitoring (HBM) of dose and biochemical effect nowadays has tremendous utility providing an efficient and cost effective means of measuring human exposure to chemical substances. HBM considers all routes of uptake and all sources which are relevant making it an ideal instrument for risk assessment and risk management. HBM can identify new chemical exposures, trends and changes in exposure, establish distribution of exposure among the general population, identify vulnerable groups and populations with higher exposures and identify environmental risks at specific contaminated sites with relatively low expenditure. The sensitivity of HBM methods moreover enables the elucidation of human metabolism and toxic mechanisms of the pollutants. So, HBM is a tool for scientists as well as for policy makers. Blood and urine are by far the most approved matrices. HBM can be done for most chemical substances which are in the focus of the worldwide discussion of environmental medicine. This especially applies for metals, PAH, phthalates, dioxins, pesticides, as well as for aromatic amines, perfluorinated chemicals, environmental tobacco smoke and volatile organic compounds. Protein adducts, especially Hb-adducts, as surrogates of DNA adducts measuring exposure as well as biochemical effect very specifically and sensitively are a still better means to estimate cancer risk than measuring genotoxic substances and their metabolites in human body fluids. Using very sophisticated but nevertheless routinely applicable analytical procedures Hb-adducts of alkylating agents, aromatic amines and nitro aromatic compounds are determined routinely today. To extend the spectrum of biochemical effect monitoring further methods should be elaborated which put up with cleavage and separation of the adducted protein molecules as a measure of sample preparation. This way all sites of adduction as well as further proteins, like serum albumin could be used for HBM. DNA-adducts indicate the mutagenicity of a chemical substance as well as an elevated cancer risk. DNA-adducts therefore would be ideal parameters for HBM. Though there are very sensitive techniques for DNA adduct monitoring like P32-postlabelling and immunological methods they lack specificity. For elucidating the mechanism of carcinogenesis and for a broad applicability and comparability in epidemiological studies analytical methods must be elaborated which are strictly specific for the chemical structure of the DNA-adduct. Current analytical possibilities however meet their borders. In HBM studies with exposure to genotoxic chemicals especially the measurement of DNA strand breaks in lymphocytes and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in white blood cells has become very popular. However, there is still a lack of well-established dose-response relations between occupational or environmental exposures and the induction of 8-OHdG or formation of strand breaks which limits the applicability of these markers. Most of the biomarkers used in population studies are covered by standard operating procedures (SOPs) as well as by internal and external quality assessment schemes. Therefore, HBM results from the leading laboratories worldwide are analytically reliable and comparable. Newly upcoming substances of environmental relevance like perfluorinated compounds can rapidly be assessed in body fluids because there are very powerful laboratories which are able to elaborate the analytical prerequisites in due time. On the other hand, it is getting more and more difficult for the laboratories to keep up with a progress in instrumental analyses. In spite of this it will pay to reach the ultimate summit of HBM because it is the only way to identify and quantify human exposure and risk, elucidate the mechanism of toxic effects and to ultimately decide if measures have to be taken to reduce exposure. Risk assessment and risk management without HBM lead to wrong risk estimates and cause inadequate measures. In some countries like in USA and in Germany, thousands of inhabitants are regularly investigated with respect to their internal exposure to a broad range of environmentally occurring substances. For the evaluation of HBM results the German HBM Commission elaborates reference- and HBM-values.

Disparity in the induction of glutathione depletion, ROS formation, poly(ADP-ribose) polymerase-1 activation, and apoptosis by quinonoid derivatives of naphthalene in human cultured cells

The purpose of this study is to examine the differences in the induction of cytotoxic effects and poly(ADP-ribose) polymerase-1 activation in human MCF-7 breast cancer cells by quinonoid derivatives of naphthalene, including 1,2-naphthalenediol (NCAT), 1,4-naphthalenediol (NHQ), 1,2-naphthoquinone (1,2-NQ), and 1,4-naphthoquinone (1,4-NQ). Results from the cytotoxic response analyses in cells indicated that all naphthalene quinonoids induced cell death in MCF-7 cells at concentrations ranging from 0.1 to 100microM where NHQ and 1,4-NQ were more efficient than NCAT and 1,2-NQ in the induction of cell death. Results from Western blot analyses confirmed that treatment of cells with NCAT and NHQ resulted in up-regulation of p53 protein expression and a significant shift in bax/bcl2 ratio, suggesting the induction of p53-dependent apoptosis in MCF-7 cells. Additionally, we observed that all naphthalene quinonoids induced increases in reactive oxygen species (ROS) formation and glutathione (GSH) depletion in MCF-7 cells. The induction of ROS formation and GSH depletion in cells by naphthalene quinonoids decreases in the rank order 1,4-NQ>NHQ>1,2-NQ approximately equal to NCAT. Further investigation indicated that least-squares estimates of the overall rates of elimination (k(e)) of naphthalene quinonoids in MCF-7 cells decreased in the rank order 1,4-NQ>1,2-NQ>NHQ>NCAT. Values of k(e) were estimated to be between 0.280h(-1)(T(1/2)=151min) and 13.8h(-1)(T(1/2)=3.05min). These results provide evidence that the para-isomeric form of naphthalene quinonoids tend to induce acute production of ROS and alterations in intracellular redox status in cells, leading to the subsequent cell death. Further, all naphthalene quinonoids induced decreases in intracellular NAD(P)H and NAD(+) in MCF-7 cells at non-cytotoxic concentrations. The reduction of intracellular NAD(P)H in cells exposed to NCAT and 1,2-NQ was blocked by two types of poly(ADP-ribose) polymerase (PARP) inhibitors whereas PARP inhibitors did not prevent the reduction of NAD(P)H in cells exposed to NHQ and 1,4-NQ. Further investigation confirmed that increases in the number of DNA single-strand breaks were detected in MCF-7 cells exposed to NCAT and 1,2-NQ as measured by the single-cell gel electrophoresis (Comet) assay whereas NHQ and 1,4-NQ did not induce increases in the number of single-strand breaks in MCF-7 cells. Overall, results from our investigation suggest that while NHQ and 1,4-NQ are more efficient in the induction of cell death, NCAT and 1,2-NQ are prone to induce depletion of NAD(P)H and NAD(+) mediated by PARP-1 activation through formation of DNA single-strand breaks in human cultured cells.

External and internal exposure to polycyclic aromatic hydrocarbons (PAH) among workers in the production of fire-proof materials – Proposal of a biological monitoring guidance value

In 1999, we introduced the German polycyclic aromatic hydrocarbons (PAH) study. The study was designed as a nation-wide investigation on workers exposed to PAH. One aim of the study was to establish biological monitoring guidance values (BMGVs) for different branches. Here, we report on the production of fire-proof materials. This branch of industry is typically confronted with high exposure to PAH and with PAH-induced occupational (cancer) diseases. One hundred and thirty-five employees participated in the course of seven sampling dates in four different plants in Germany. External exposure was determined by personal air monitoring of the 16 EPA-PAH. Human biological monitoring was accomplished by the determination of 1-hydroxypyrene and monohydroxyphenanthrenes in post-shift spot urine samples. Concentrations of PAH in the air of the workplaces ranged up to 1102.6microg/m(3). Maximum benzo[a]pyrene concentration was 38.2microg/m(3). The internal PAH exposure of workers was much higher compared with that of the general population. Median concentration for 1-hydroxypyrene was 6.4microg/g creatinine (maximum 279.6, 90th percentile 23.9microg/g creatinine) and for the sum of monohydroxyphenanthrene metabolites 13.3microg/g creatinine (maximum 313.4, 90th percentile 70.8microg/g creatinine). The following BMGVs for the non-smokers of this branch of industry are proposed: for 1-hydroxypyrene 18microg/g creatinine and for the sum of hydroxyphenanthrenes 77microg/g creatinine in urine measured at the end of the shift.

8-Hydroxy-2'-deoxyguanosine as a marker of oxidative DNA damage related to occupational and environmental exposures

Oxidative DNA damage is considered to play an important role in pathophysiological processes, ageing and cancer. So far major interest has been on measuring 8-hydroxy-2'-deoxyguanosine (8-OHdG), the preferred methods relying on HPLC or GC-mass spectrometry. The high biological relevance of 8-OHdG is due to its ability to induce G-->T transversions, which are among the most frequent somatic mutations found in human cancers. Effects of workplace exposures on the level of white blood cell 8-OHdG or urinary 8-OHdG have been reported with controversial results. Exposures examined include asbestos, azo-dyes, benzene, fine particulate matter (PM(2.5)), glassworks, polycyclic aromatic hydrocarbons (PAHs), rubber manufacturing, silica, metals, styrene, toluene and xylenes. The available data indicate that there is still a lack of well established dose-response relations between occupational or environmental exposures and the induction of 8-OHdG. Smoking has been most consistently identified as a confounder for 8-OHdG, but various occupational studies did not reveal higher levels of 8-OHdG in smokers. Despite the conflicting results, the reported studies show promise for 8-OHdG as a biomarker of oxidative stress associated with chemical exposure. However, there are critical aspects related to the analytical challenge, artifactual production of 8-OHdG, inter- and intra-individual variation, confounding factors and inter-laboratory differences, implying that further work is needed to reach a consensus on the background level of 8-OHdG.

Occupational exposure in airport personnel: characterization and evaluation of genotoxic and oxidative effects

Airport personnel can be exposed to several polycyclic aromatic hydrocarbons (PAHs) from jet fuel vapours, jet fuel combustion products and diesel exhaust. The aim of this study was to characterize the exposure and to evaluate genotoxic and oxidative effects in airport personnel (n=41) in comparison with a selected control group (n=31). Environmental monitoring of exposure was carried out analysing 23 PAHs on air samples collected from airport apron, airport building and terminal/office area during 5 working days. The urinary 1-hydroxy-pyrene (1-OHP) following 5 working days, was used as biomarker of exposure. Genotoxic effects and early direct-oxidative DNA damage were evaluated by micronucleus (MN) and Fpg-modified comet assay on lymphocytes and exfoliated buccal cells, and by chromosomal aberrations (CA) and sister chromatid exchange (SCE) analyses. For comet assay, tail moment (the product of comet relative tail intensity and length) values from Fpg-enzyme treated cells (TMenz) and from untreated cells (TM) were used as parameters of oxidative and direct DNA damage, respectively. We found 27,703 microg/m(3) total PAHs in airport apron, 17,275 microg/m(3) in airport building and 9,494 microg/m(3) in terminal/office area. Urinary OH-pyrene did not show differences between exposed and controls. The exposed group showed a higher mean value of SCE frequency in respect to controls (4.6 versus 3.8) and an increase (1.3-fold) of total structural CA in particular breaks (up to 2.0-fold) and fragments (0.32% versus 0.00%), whereas there were no differences of MN frequency in both cellular types. Comet assay evidenced in the exposed group a higher value in respect to controls of mean TM and TMenz in both exfoliated buccal cells (TM 118.87 versus 68.20, p=0.001; TMenz 146.11 versus 78.32, p<0.001) and lymphocytes (TM 43.01 versus 36.01, p=0.136; TMenz 55.86 versus 43.98, p=0.003). An oxidative DNA damage was found, for exfoliated buccal cells in the 9.7% and for lymphocytes in the 14.6% of exposed in respect to the absence in controls. Our findings furnish a useful contribution to the characterization of civil airport exposure and suggest the use of comet assay on exfoliated buccal cells to assess the occupational exposure to mixtures of inhalable pollutants at low doses since these cells represent the target tissue for this exposure and are obtained by non-invasive procedure.

Assessment of DNA Damage in WBCs of Workers Occupationally Exposed to Fumes and Aerosols of Bitumen

We conducted a cross-shift study with 66 bitumen-exposed mastic asphalt workers and 49 construction workers without exposure to bitumen. Exposure was assessed using personal monitoring of airborne bitumen exposure, urinary 1-hydroxypyrene (1-OHP), and the sum of 1-, 2 + 9-,3-,4-hydroxyphenanthrene (OHPH). Genotoxic effects in WBC were determined with nonspecific DNA adduct levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and the formation of DNA strand breaks and alkali-labile sites. Concentration of fumes and aerosols of bitumen correlated significantly with the concentrations of 1-OHP and OHPH after shift (r(s) = 0.27; P = 0.03 and r(s) = 0.55; P < 0.0001, respectively). Bitumen-exposed workers had more DNA strand breaks than the reference group (P < 0.0001) at both time points and a significant correlation with 1-OHP and OHPH in the postshift urines (r(s) = 0.32; P = 0.001 and r(s) = 0.27; P = 0.004, respectively). Paradoxically, we measured higher levels of DNA strand breaks, although not significant, in both study groups before shift. 8-OxodGuo adduct levels did not correlate with DNA strand breaks. Further, 8-oxodGuo levels were associated neither with personal exposure to bitumen nor with urinary metabolite concentrations. Significantly more DNA adducts were observed after shift not only in bitumen-exposed workers but also in the reference group. Only low-exposed workers had significantly elevated 8-oxodGuo adduct levels before as well as after shift (P = 0.0002 and P = 0.02, respectively). Our results show that exposure to fumes and aerosols of bitumen may contribute to an increased DNA damage assessed with strand breaks.

Sperm DNA damage correlates with polycyclic aromatic hydrocarbons biomarker in coke-oven workers

OBJECTIVES

The aim was to determine whether occupational exposure to polycyclic aromatic hydrocarbons (PAHs) in men has adverse effect on semen quality.

METHODS

Forty-eight coke-oven workers, including 16 topside-oven (TO) workers and 32 sideoven (SO) workers, were studied. Ambient PAHs exposure, urinary 1-hydroxypyrene (1-OHP) levels, and parameters of semen quality were determined.

RESULTS

TO workers had significantly higher ambient PAHs exposure (3,436.1+/-3,411.0 vs. 1,123.1+/-1,829.3 ng/m3, P < 0.01), urinary 1-OHP levels (207.8+/-176.4 vs. 54.0+/-44.8 microg/g, P < 0.001), frequency of oligospermia (18.8 vs. 0%, P < 0.05), and morphological abnormality in sperm (32.3 vs. 14.6%, P < 0.01) than SO workers. Among cigarette smokers, TO workers had significantly higher rates of DNA denaturation in spermatozoa (alphaT) and percentage of sperm with increased DNA denaturation (COMP alphaT) levels than SO workers (246.2+/-49.5 vs. 198.1+/-30.3 for alphaT; 34.8+/-14.4 vs. 19.3+/-13.9% for COMP alphaT, P < 0.05). There was a positive correlation between urinary 1-OHP and alphaT, COMP alphaT, and abnormal sperm morphology and a tenfold increase in urinary 1-OHP associated with a 2.35-fold increase in alphaT, as well as a 1.07-fold increase in percentage of sperm with abnormal morphology.

CONCLUSIONS

A potential risk of sperm dysfunction should be considered for workers occupationally exposed to high levels of PAHs. Cigarette smoking may aggravate this risk. Urinary 1-OHP can be used as a biomarker predicting sperm dysfunction.