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.

Simple and reliable method to simultaneously determine urinary 1- and 2-naphthol using in situ derivatization and gas chromatography-mass spectrometry for biological monitoring of naphthalene exposure in occupational health practice

OBJECTIVES

The aim of this study was to develop and validate a simple and reliable gas chromatography-mass spectrometry (GC-MS) method to simultaneously determine urinary 1-naphthol (1-NAP) and 2-naphthol (2-NAP) for biological monitoring of occupational exposure to naphthalene.

METHODS

NAPs were derivatized in situ with acetic anhydride after enzymatic hydrolysis, extracted with n-hexane, and analyzed using GC-MS. Validation of the proposed method was conducted in accordance with US Food and Drug Administration guidance. A final validation was performed by analyzing a ClinChek® -Control for phenolic compounds.

RESULTS

The linearity of calibration curves was indicated by a high correlation coefficient (>0.999) in the concentration range 1-100 μg/L for each NAP. The limits of detection and quantification for each NAP were 0.30 and 1.00 μg/L, respectively. The recovery was 90.8%-98.1%. The intraday and interday accuracies, expressed as the deviation from the nominal value, were 92.2%-99.9% and 93.4%-99.9%, respectively. The intraday and interday precision, expressed as the relative standard deviation, was 0.3%-3.9% and 0.4%-4.1%, respectively. The ClinChek® values obtained using our method were sufficiently accurate.

CONCLUSIONS

The proposed method is simple, reliable, and appropriate for routine analyses, and is useful for biological monitoring of naphthalene exposure in occupational health practice.

Alterations in platelet indices link polycyclic aromatic hydrocarbons toxicity to low-grade inflammation in preschool children

BACKGROUND

Environmental exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) can disturb the immune response. However, the effect of PAHs on low-grade inflammation related to platelets in humans is unknown.

OBJECTIVES

We investigated the association of PAH exposure with low-grade inflammation and platelet parameters in healthy preschoolers.

METHODS

The present study recruited 239 participants, aged 2-7 years, from an electronic-waste (e-waste)-exposed (n = 118) and a reference (n = 121) area. We measured ten urinary PAH metabolites, four types of immune cells and cytokines, and seven platelet parameters, and compared their differences between children from the two groups. Spearman correlation analysis was performed to explore the potential risk factors for PAH exposure and the associations between urinary monohydroxylated PAHs (OH-PAHs) and biological parameters. Associations between urinary PAH metabolites and platelet indices were analyzed using quantile regression models. Mediation analysis was used to understand the relationship between urinary total hydroxynaphthalene (ΣOHNa) and interleukin (IL)-1β through seven platelet indices, as mediator variables.

RESULTS

We found higher urinary monohydroxylated PAH (OH-PAH) concentrations, especially 1-hydroxynaphthalene (1-OHNa) and 2-hydroxynaphthalene (2-OHNa), in children from the e-waste-exposed group than in the reference group. These were closely associated with child personal habits and family environment. A decreased lymphocyte ratio and increased pro-inflammatory cytokines, such as gamma interferon-inducible protein (IP)-10 and IL-1β, were found in the e-waste-exposed children. After adjustment for confounding factors, significantly negative correlations were found between levels of mean platelet volume (MPV), platelet distribution width (PDW), platelet-large cell ratio (P-LCR) and ratio of mean platelet volume to platelet count (MPVP) and OH-PAHs. In addition, ΣOHNa was positively associated with IL-1β mediated through MPV, PDW, P-LCR, and ratio of platelet count to lymphocyte count (PLR).

CONCLUSIONS

Platelet indices were significantly associated with the changes in urinary OH-PAH levels, which may can be regarded as effective biomarkers of low-grade inflammation resulting from low PAH exposure in healthy children.

Maternal urinary 2-hydroxynaphthalene and birth outcomes in Taiyuan, China

BACKGROUND

Naphthalene is the simplest polycyclic aromatic hydrocarbon (PAH). It is easily emitted into the atmosphere, posing a significant risk to human health. However, limited studies have described the impact of naphthalene exposure on birth outcomes. In this study, we investigated the association between the maternal urinary metabolites of naphthalene, 2-hydroxynaphthalene (2-OH NAP), and birth outcomes.

METHOD

In the present study, four urinary PAH metabolites were measured in 263 pregnant women during late pregnancy. Multiple linear regression analysis was used to analyze the relationship between the concentrations of 2-OH NAP and birth outcomes, and restricted cubic spline models were further used to examine the shapes of the dose-response association.

RESULT

General linear models showed that prenatal urinary 2-OH NAP was associated with lower birth weight (BW) (- 4.38% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.049) and higher cephalization index (CI) (4.30% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.038). These associations were linear and significant when 2-OH NAP was modeled as a continuous variable in restricted cubic spline models (P _linear = 0.0293 for 2-OH NAP and BW; P _linear = 0.0326 for 2-OH NAP and CI). Multiple linear regression data indicated that each 1 ln-unit increase in 2-OH NAP was significantly associated with a 2.09 g/cm increase in the CI. The associations among 2-OH NAP, BW, and CI were also observed in a subset of participants residing close to arterial traffic.

CONCLUSION

Our data indicated that prenatal exposure to naphthalene had an adverse effect on fetal birth outcomes, especially the brain development index. Reduced exposure to naphthalene may improve newborn health outcomes. In Taiyuan, naphthalene may result from traffic pollution.

2-Naphthol Levels and Allergic Disorders in Children

Background: The measurement of polycyclic aromatic hydrocarbons (PAH) in ambient air is quite difficult to perform. Using urine biomarkers of PAH such as 2-naphthol is one approach to this problem. This study explored the association between urine 2-naphthol levels and allergic diseases. The associations between 2-naphthol levels and oxidative stress biomarkers for the possible disease pathogenesis were also investigated. Method: A total of 453 kindergarten children from the (Childhood Environment and Allergic Diseases Study) CEAS cohort with urine samples were recruited. Urine 2-naphthol levels were measured by high-performance liquid chromatography mass spectrometry (HPLC-MS/MS) and markers of oxidative stress (8OHdG) were measured by enzyme-linked immunosorbent assays (ELISA). Information on environmental risk factors and allergic diseases were also collected. The association between 2-naphthol levels, 8OHdG levels, IgE, and allergic diseases were evaluated by multivariate linear regression and logistic regression. Results: Levels of 2-naphthol were positively correlated with 8OHdG levels. A one ln-unit increase in the 2-naphthol level was positively associated to 8OHdG levels (per ln-unit: β = 100.61, p < 0.001). When dividing 2-naphthol levels into quartiles, asthma was significantly associated with 2-naphthol levels at a concentration of >1.60 ng/mL (adjusted OR: 3.14, 95% CI 1.34–7.35). Conclusion: Urine 2-naphthol levels are associated with markers of oxidative stress and the risk of allergic diseases in young children.

Prenatal urinary polycyclic aromatic hydrocarbon metabolites, global DNA methylation in cord blood, and birth outcomes: A cohort study in China

BACKGROUND

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) is a potential risk factor for adverse birth outcomes. Epigenetic mechanisms may play a key role in which PAHs exert its effects.

OBJECTIVE

Our study aimed to examine whether prenatal PAH exposure was associated with adverse birth outcomes and altered DNA methylation and to explore potential mediating roles of DNA methylation.

METHODS

Ten urinary PAH metabolites were measured from 106 pregnant women during late pregnancy in a Chinese cohort study. Cord blood DNA methylation in long interspersed nucleotide element-1 (LINE-1) and Alu repetitive elements as surrogates of global DNA methylation was analyzed by bisulfite pyrosequencing. Multivariable linear regression was used to estimate the associations of urinary PAH metabolites with birth outcomes and DNA methylation, and a mediation analysis was also conducted.

RESULTS

Prenatal urinary 2-hydroxynaphthalene (2-OHNa), ∑OHNa (sum of 1- and 2-OHNa), and sum of monohydroxy-PAH (∑OH-PAHs) were associated with lower birth length (e.g., -0.80%, 95% CI: -1.39%, -0.20% for the third vs. first tertile of 2-OHNa; p for trend = 0.01). Prenatal urinary 2-OHNa and 1-hydroxyphenanthrene (1-OHPh) were associated with lower Alu and LINE-1 methylation (e.g., -1.88%, 95% CI: -3.73%, -0.10% for the third vs. first tertile tertile of 2-OHNa in Alu methylation; p for trend = 0.04). Mediation analysis failed to show a mediator effect of global DNA methylation in the association between prenatal urinary OH-PAHs and birth outcomes.

CONCLUSIONS

Prenatal specific PAH exposures are associated with decreased birth length and global DNA methylation. However, global DNA methylation does not mediate the associations of prenatal PAH exposure with birth outcomes. Further studies are needed to confirm the results.

Association of atmospheric concentrations of polycyclic aromatic hydrocarbons with their urinary metabolites in children and adolescents

This study aims to determine the atmospheric concentrations of particulate matter 2.5 (PM_2.5)-bounded polycyclic aromatic hydrocarbons (PAHs) and their association with their urinary metabolites in children and adolescents. This study was conducted from October 2014 to March 2016 in Isfahan, Iran. We measured 16 species of PAHs bounded to PM_2.5 by gas chromatography mass spectrometry (GC/MS) from 7 parts of the city. Moreover, PAH urinary metabolites were measured in 186 children and adolescents, randomly selected from households. Urinary metabolites consisted of 1-hydroxy naphthalene (1-naphthol), 2-hydroxy naphthalene (2-naphthol), 9-hydroxy phenanthrene (9-phenanthrol), and 1-hydroxy pyrene using GC/MS. Considering the short half-lives of PAHs, we measured the metabolites twice with 4 to 6 months of time interval. We found that the ambient concentrations of PAHs were significantly associated with their urinary metabolites. 1-hydroxy naphthalene and 2-hydroxy naphthalene concentrations showed an increase of 1.049 (95% CI: 1.030, 1.069) and 1.047 (95% CI: 1.025, 1.066) for each unit increase (1 ng/m³) in ambient naphthalene. Similarly, 1-hydroxy pyrene showed an increase of 1.009 (95% CI: 1.006-1.011) for each unit increase (1 ng/m³) in ambient pyrene concentration after adjustment for body mass index, physical activity level, urinary creatinine, age, and sex. The association of urinary 9-hydroxyphenanthrene and ambient phenantherene was significant in the crude model; however after adjustment for the abovementioned covariates, it was no more significant. We found significant correlations between exposure to ambient PM_2.5-bounded PAHs and their urinary excretion. Considering the adverse health effects of PAHs in the pediatric age group, biomonitoring of PAHs should be underscored; preventive measures need to be intensified.

Biomonitoring Human Exposure to Household Air Pollution and Association with Self-reported Health Symptoms - A Stove Intervention Study in Peru

BACKGROUND

Household air pollution (HAP) from indoor biomass stoves contains harmful pollutants, such as polycyclic aromatic hydrocarbons (PAHs), and is a leading risk factor for global disease burden. We used biomonitoring to assess HAP exposure and association with self-reported symptoms in 334 non-smoking Peruvian women to evaluate the efficacy of a stove intervention program.

METHODS

We conducted a cross-sectional study within the framework of a community randomized control trial. Using urinary PAH metabolites (OH-PAHs) as the exposure biomarkers, we investigated whether the intervention group (n=155, with new chimney-equipped stoves) were less exposed to HAP compared to the control group (n=179, with mostly open-fire stoves). We also estimated associations between the exposure biomarkers, risk factors, and self-reported health symptoms, such as recent eye conditions, respiratory conditions, and headache.

RESULTS

We observed reduced headache and ocular symptoms in the intervention group than the control group. Urinary 2-naphthol, a suggested biomarker for inhalation PAH exposure, was significantly lower in the intervention group (GM with 95% CI: 13.4 [12.3, 14.6] μg/g creatinine) compared to control group (16.5 [15.0, 18.0] μg/g creatinine). Stove type and/or 2-naphthol was associated with a number of self-reported symptoms, such as red eye (adjusted OR with 95% CI: 3.80 [1.32, 10.9]) in the past 48h.

CONCLUSIONS

Even with the improved stoves, the biomarker concentrations in this study far exceeded those of the general populations and were higher than a no-observed-genotoxic-effect-level, indicating high exposure and a potential for increased cancer risk in the population.

Urinary concentrations of organophosphate and carbamate pesticides in residents of a vegetarian community

Few population studies have measured urinary levels of pesticides in individuals with vegan, vegetarian, or organic diets. The objectives of this study were to evaluate whether a vegan/vegetarian diet was associated with increased exposure to organophosphate and carbamate pesticides, and to evaluate the impact of organic consumption on pesticide exposure in vegans and vegetarians. In the current pilot study conducted in 2013-2014, we collected spot urine samples and detailed 24h recall dietary data in 42 adult residents of Amirim, a vegetarian community in Northern Israel. We measured urinary levels of non-specific organophosphate pesticide metabolites (dialkylphosphates, (DAPs)) and specific metabolites of the current-use pesticides chlorpyrifos (3,5,6-trichloro-2-pyridinol (TCPy)), propoxur (-isopropoxyphenol (IPPX)), and carbaryl (1-naphthol). Six DAP metabolites were detected in between 67 and 100% of urine samples, with highest geometric mean concentrations for dimethylphosphate (19.2μg/g). Creatinine-adjusted median concentrations of total DAPs and of TCPy were significantly higher in Amirim residents compared to the general Jewish population in Israel (0.29μmol/g compared to 0.16, p<0.05 for DAPs and 4.32μg/g compared to 2.34μg/g, p<0.05 for TCPy). Within Amirim residents, we observed a positive association between vegetable intake and urinary TCPy levels (rho=0.47, p<0.05) and lower median total dimethyl phosphate levels in individuals reporting that >25% of the produce they consume is organic (0.065μmol/L compared to 0.22, p<0.05). Results from this pilot study indicate relatively high levels of urinary organophosphate pesticide metabolite concentrations in residents of a vegetarian community, a positive association between vegetable intake and urinary levels of a chlorpyrifos specific metabolite, and lower levels of total dimethyl phosphate in individuals reporting higher intake of organic produce. Results suggest that consumption of organic produce may offer some protection from increased exposure to organophosphate pesticide residues in vegetarians.

Genome-Wide Analysis of DNA Methylation and Cigarette Smoking in a Chinese Population

BACKGROUND

Smoking is a risk factor for many human diseases. DNA methylation has been related to smoking, but genome-wide methylation data for smoking in Chinese populations is limited.

OBJECTIVES

We aimed to investigate epigenome-wide methylation in relation to smoking in a Chinese population.

METHODS

We measured the methylation levels at > 485,000 CpG sites (CpGs) in DNA from leukocytes using a methylation array and conducted a genome-wide meta-analysis of DNA methylation and smoking in a total of 596 Chinese participants. We further evaluated the associations of smoking-related CpGs with internal polycyclic aromatic hydrocarbon (PAH) biomarkers and their correlations with the expression of corresponding genes.

RESULTS

We identified 318 CpGs whose methylation levels were associated with smoking at a genome-wide significance level (false discovery rate < 0.05), among which 161 CpGs annotated to 123 genes were not associated with smoking in recent studies of Europeans and African Americans. Of these smoking-related CpGs, methylation levels at 80 CpGs showed significant correlations with the expression of corresponding genes (including RUNX3, IL6R, PTAFR, ANKRD11, CEP135 and CDH23), and methylation at 15 CpGs was significantly associated with urinary 2-hydroxynaphthalene, the most representative internal monohydroxy-PAH biomarker for smoking.

CONCLUSION

We identified DNA methylation markers associated with smoking in a Chinese population, including some markers that were also correlated with gene expression. Exposure to naphthalene, a byproduct of tobacco smoke, may contribute to smoking-related methylation.

CITATION

Zhu X, Li J, Deng S, Yu K, Liu X, Deng Q, Sun H, Zhang X, He M, Guo H, Chen W, Yuan J, Zhang B, Kuang D, He X, Bai Y, Han X, Liu B, Li X, Yang L, Jiang H, Zhang Y, Hu J, Cheng L, Luo X, Mei W, Zhou Z, Sun S, Zhang L, Liu C, Guo Y, Zhang Z, Hu FB, Liang L, Wu T. 2016. Genome-wide analysis of DNA methylation and cigarette smoking in Chinese. Environ Health Perspect 124:966-973; http://dx.doi.org/10.1289/ehp.1509834.

Monitoring exposure to polycyclic aromatic hydrocarbons in an Australian population using pooled urine samples

Integrated exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). The aim of this study was to provide the first assessment of exposure to PAHs in a large sample of the population in Queensland, Australia including exposure to infant (0-4years). De-identified urine specimens, obtained from a pathology laboratory, were stratified by age and sex, and pooled (n=24 pools of 100) and OH-PAHs were measured by gas chromatography-isotope dilution-tandem mass spectrometry. Geometric mean (GM) concentrations ranged from 30ng/L (4-hydroxyphenanthrene) to 9221ng/L (1-naphthol). GM of 1-hydroxypyrene, the most commonly used PAH exposure biomarker, was 142ng/L. The concentrations of OH-PAHs found in this study are consistent with those in developed countries and lower than those in developing countries. We observed no association between sex and OH-PAH concentrations. However, we observed lower urinary concentrations of all OH-PAHs in samples from infants (0-4years), children (5-14years) and the elderly (>60year old) compared with samples from other age groups (15-29, 30-44 and 45-59years) which may be attributed to age-dependent behaviour-specific exposure sources.

Biomarkers for polycyclic aromatic hydrocarbons and serum liver enzymes

BACKGROUND

Limited evidence suggests that human liver toxicity is associated with exposure to polycyclic aromatic hydrocarbons (PAHs).

METHODS

The association of urinary PAH metabolites with serum liver enzymes was tested among 288 workers at a petrochemical plant, using a general linear model (GLM) and multiple logistic regression.

RESULTS

Urine 2-naphthol levels were positively correlated with serum AST after adjustment for covariates in GLM. Comparing third tertile versus first tertile of 2-naphthol levels, the odds ratios (OR) were elevated for abnormal serum AST levels [OR = 4.1 (95%CI 1.6-10.2)] and abnormal serum ALT levels [OR = 2.4 (95%CI 1.2-4.9)].

CONCLUSIONS

Although confounding by alcohol intake was not completely ruled out, our findings demonstrate an association between PAHs exposure and elevation in serum liver enzymes. Urinary 2-naphthol is a biomarker of exposure to PAHs that is associated with liver toxicity.

Isolation and identification of twelve metabolites of isocorynoxeine in rat urine and their neuroprotective activities in HT22 cell assay

Isocorynoxeine, one of the major alkaloids from Uncaria Hook, shows the effects of lowering blood pressure, vasodilatation, and protection against ischemia-induced neuronal damage. In this paper, the metabolism of isocorynoxeine was investigated in rats. Twelve metabolites and the parent drug were isolated by using solvent extraction and repeated chromatographic methods, and determined by spectroscopic methods including UV, MS, NMR, and CD experiments. Seven new compounds were identified as 11-hydroxyisocorynoxeine, 5-oxoisocorynoxeinic acid-22-O-β-D-glucuronide, 10-hydroxyisocorynoxeine, 17-O-demethyl-16,17-dihydro-5-oxoisocorynoxeine, 5-oxoisocorynoxeinic acid, 21-hydroxy-5-oxoisocorynoxeine, and oxireno[18, 19]-5-oxoisocorynoxeine, together with six known compounds identified as isocorynoxeine, 18,19-dehydrocorynoxinic acid, 18,19-dehydrocorynoxinic acid B, corynoxeine, isocorynoxeine-N-oxide, and corynoxeine-N-oxide. Possible metabolic pathways of isocorynoxeine are proposed. Furthermore, the activity assay for the parent drug and some of its metabolites showed that isocorynoxeine exhibited a significant neuroprotective effect against glutamate-induced HT22 cell death at the maximum concentration. However, little or weak neuroprotective activities were observed for M-3, M-6, M-7, and M-10. Our present study is important to further understand their metabolic fate and disposition in humans.

Urinary and breast milk biomarkers to assess exposure to naphthalene in pregnant women: an investigation of personal and indoor air sources

BACKGROUND

Naphthalene exposures for most non-occupationally exposed individuals occur primarily indoors at home. Residential indoor sources include pest control products (specifically moth balls), incomplete combustion such as cigarette smoke, woodstoves and cooking, some consumer and building products, and emissions from gasoline sources found in attached garages. The study aim was to assess naphthalene exposure in pregnant women from Canada, using air measurements and biomarkers of exposure.

METHODS

Pregnant women residing in Ottawa, Ontario completed personal and indoor air sampling, and questionnaires. During pregnancy, pooled urine voids were collected over two 24-hour periods on a weekday and a weekend day. At 2-3 months post-birth, they provided a spot urine sample and a breast milk sample following the 24-hour air monitoring. Urines were analyzed for 1-naphthol and 2-naphthol and breast milk for naphthalene. Simple linear regression models examined associations between known naphthalene sources, air and biomarker samples.

RESULTS

Study recruitment rate was 11.2% resulting in 80 eligible women being included. Weekday and weekend samples were highly correlated for both personal (r = 0.83, p < 0.0001) and indoor air naphthalene (r = 0.91, p < 0.0001). Urine specific gravity (SG)-adjusted 2-naphthol concentrations collected on weekdays and weekends (r = 0.78, p < 0.001), and between pregnancy and postpartum samples (r = 0.54, p < 0.001) were correlated.Indoor and personal air naphthalene concentrations were significantly higher post-birth than during pregnancy (p < 0.0001 for signed rank tests); concurrent urine samples were not significantly different. Naphthalene in breast milk was associated with urinary 1-naphthol: a 10% increase in 1-naphthol was associated with a 1.6% increase in breast milk naphthalene (95% CI: 0.2%-3.1%). No significant associations were observed between naphthalene sources reported in self-administered questionnaires and the air or biomarker concentrations.

CONCLUSIONS

Median urinary concentrations of naphthalene metabolites tended to be similar to (1-naphthol) or lower (2-naphthol) than those reported in a Canadian survey of women of reproductive age. Only urinary 1-naphthol and naphthalene in breast milk were associated. Potential reasons for the lack of other associations include a lack of sources, varying biotransformation rates and behavioural differences over time.

[Polycyclic aromatic hydrocarbons monohydroxy metabolites level in urine of general population in eight provinces of China]

OBJECTIVE

To assess the levels of polycyclic aromatic hydrocarbons monohydroxy metabolites in urine of general population in China among 8 provinces, provide the baseline of the metabolites in the general population.

METHODS

From 2009 to 2010, 18 120 subjects of general population aged 6-60 years old were recruited from 24 areas among 8 provinces in east, west and central areas of China mainland by cluster random sampling. The information of the living environment and health condition were collected by questionnaire and spot urine samples were collected, 4 680 urine samples were analysed by high performance liquid chromatography with tandem mass spectrometry, and monohydroxy metabolites distribution in urine among groups of gender and ages were analysed.

RESULTS

Geometric means (GM) of 2-naphthol, 1-naphthol, 3-phenanthrol and 1-hydroxypyrene concentration in urine (95%CI) were 1.85 (1.75-1.95), 1.55 (1.50-1.61), 0.57 (0.54-0.59) and 0.82 (0.78-0.85) µg/L, respectively;and median are 2.44, <0.50, 0.72 and 0.90 µg/L, respectively. The concentration between male and female were significantly different (P < 0.01), and the concentration among the groups of population were significantly different (P < 0.01), the GM of 2-naphthol among the groups of population aged 6-12, 13-16, 17-20, 21-30, 31-45 and 46-60 years old were 1.60, 1.56, 1.69, 2.23, 1.91 and 1.86 µg/L (χ(2) = 17.90, P < 0.01), the GM of 1-naphthol in the groups were 1.30, 1.16, 1.53, 1.68, 1.80 and 1.52 µg/L (χ(2) = 76.22, P < 0.01), the GM of 3-phenanthrol in the groups were 0.78, 0.76, 0.55, 0.42, 0.50 and 0.99 µg/L (χ(2) = 66.48, P < 0.01), the GM of 1-hydroxypyrene in the groups were 0.77,0.64, 1.00, 0.84, 0.84 and 0.57 µg/L (χ(2) = 51.48, P < 0.01), respectively.

CONCLUSION

The distribution of monohydroxy metabolites levels in urine of general population were different, it provided a basic data for the further study of polycyclic aromatic hydrocarbons biomonitoring in the population.

Personal exposure levels of PAHs in the general population in northern rural area of Jiangsu Province, China

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds that are produced by incomplete combustion of organic matters. Studies in humans have shown associations between PAHs exposure and development of cancers. Urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) are a class of PAH metabolites used as biomarkers for estimating human exposure to PAHs. We collected 332 urinary samples from a nonoccupational population in northern rural area of Jiangsu. Levels of 2-hydroxynathalene (2-OHN), 2-hydroxyfluorene (2-OHF) and 1-hydroxypyrene (1-OHP) were measured as biomarkers to assess body PAHs burdens. Three PAH metabolites were detected in more than 80% of urinary samples. After being adjusted with urinary creatinine concentration, the urinary concentrations were determined as 2-OHF > 1-OHP > 2-OHN in terms. The medians of 2-OHN, 2-OHF, 1-OHP for the general population were 1.74, 30.01, 25.24 μmoL/moL creatinine, respectively. The results demonstrated that nonoccupational populations in northern rural area of Jiangsu were exposed to extremely high PAHs. The urinary concentration (median and geometric mean) of 2-OHN,2-OHF,1-OHP in males (1.90, 0.37 ± 0.46; 34.90, 1.53 ± 0.41; 27.84, 1.52 ± 0.29 μmoL/moL creatinine, respectively) was slightly higher than in females (1.56, 0.32 ± 0.42; 29.60, 1.48 ± 0.40; 23.13, 1.49 ± 0.32 μmoL/moL creatinine, respectively). However, only 2-OHN was different significantly between males and females.

Naphthalene biomarkers and relationship with hemoglobin and hematocrit in White, Black, and Hispanic adults: results from the 2003-2004 National Health and Nutrition Examination Survey

Naphthalene is an important contaminant in indoor and outdoor air. Acute overexposure can have toxic effects, resulting in hemolysis. There have been no studies evaluating the impact of environmental exposure on red blood cell indices. We examined 1- and 2-hydroxynaphthalene urinary metabolites (NAP1 and NAP2) in non-Hispanic White, non-Hispanic Black, and Mexican-American adults in the USA and their relationship with hemoglobin (Hb) and hematocrit (HCT). Using the 2003-2004 National Health and Nutrition Examination Survey data, weighted generalized linear regression analyses were used to examine the association between Hb (in grams per deciliter) and HCT (in percent) with NAP1 and NAP2 (per 100,000 ng/L). Beta coefficients ± SE are reported. NAP1 and NAP2 were highest in non-Hispanic Blacks, followed by non-Hispanic Whites, and lowest in Mexican-American adults. There was a positive association between NAP1 and Hb (0.39 ± 0.11, p = 0.0034) and HCT (1.14 ± 0.28, p = 0.0009) after adjusting for age, gender, race, education, and smoking. Stratified analysis by smoking showed similar results with the association being stronger for smokers (Hb 0.63 ± 0.23, p = 0.02; HCT 1.43 ± 0.79, p = 0.09) than nonsmokers (Hb 0.34 ± 0.14, p = 0.03; HCT 1.08 ± 0.42, p = 0.02). The association was also stronger for non-Hispanic blacks (Hb 0.54 ± 0.20, p = 0.02; HCT 1.43 ± 0.55, p = 0.02) than for non-Hispanic whites (Hb 0.37 ± 0.18, p = 0.06; HCT 1.20 ± 0.51, p = 0.03) and was not significant for Mexican-Americans (Hb 0.30 ± 1.7, p = 0.10; HCT 0.99 ± 0.52, p = 0.08). NAP2 was not significantly associated with Hb or HCT. The observed disparity in NAP1 and NAP2 levels by race/ethnicity is consistent with published literature. The origin of these differences in exposure is unclear but may reflect differences in environmental exposure as well as genetic susceptibility. The positive association between NAP1 with HCT and Hb is an unexpected finding. Further research is needed to understand the possible biological mechanisms or other explanations for this association.

The relationships between pesticide metabolites and neurobehavioral test performance in the third National Health and Nutrition Examination Survey

Regression analysis was used to estimate and test for relationships between urinary pesticide metabolites and neurobehavioral test performance in adults, 20 to 59 years old, participating in the third National Health and Nutrition Examination Survey. The 12 pesticide metabolites included 2 naphthols, 8 phenols, a phenoxyacetic acid, and a pyridinol. The 3 neurobehavioral tests included in the survey were simple reaction time, symbol-digit substitution, and serial digit learning. As the 2,4-dichlorophenol, 2,5-dichlorophenol, and the pentachlorophenol concentrations increased, performance on the serial digit learning test improved. As the 2,5-dichlorophenol concentration increased, performance on the symbol-digit substitution test improved. At low concentrations, the parent compounds of these metabolites may act at acetylcholine and γ-aminobutyric acid synapses in the central nervous system to improve neurobehavioral test performance.

[Effects of smoking on the concentrations of urinary 10 metabolites of polycyclic aromatic hydrocarbons in coke oven workers]

OBJECTIVE

To explore the effects of smoking on urinary 10 metabolites of polycyclic aromatic hydrocarbons (PAHs) in the coke oven workers.

METHODS

Occupational health examination was performed on 1401 coke oven workers in one coking plant, their urine were collected respectively. The concentrations of the ten monohydroxy polycyclic aromatic hydrocarbons in urine were detected by gas chromatography/mass spectrometry. The 1401 workers were divided into four groups, namely control, adjunct workplaces, bottom and side, top group according to their workplaces and the different concentrations of PAHs in the environment. The concentrations of the ten monohydroxy polycyclic aromatic hydrocarbons between smokers and nonsmokers in each workplace group were compared using analysis of covariance, respectively.

RESULTS

The levels of concentrations of the sixteen polycyclic aromatic hydrocarbons we detected at control were significantly higher than those at other areas (P < 0.05). Comparing the ten monohydroxy polycyclic aromatic hydrocarbons levels between smokers and nonsmokers, the levels of 1-hydroxynaphthalene and 2-hydroxynaphthalene among smokers were higher than nonsmokers with statistically significance in control, adjunct workplaces, bottom and side and top groups (P < 0.05). However, the levels of 1-hydroxypyrene had no statistically significant differences between the four areas.

CONCLUSION

Urinary 1-hydroxynaphthalene and 2-hydroxynaphthalene may be used as biomarkers for the impact of smoking on monohydroxy polycyclic aromatic hydrocarbons in the coke oven workers.

Korea National Survey for Environmental Pollutants in the human body 2008: 1-hydroxypyrene, 2-naphthol, and cotinine in urine of the Korean population

The Korea National Survey for Environmental Pollutants in the human body conducts representative Korean population studies, which were first initiated in 2005 in Korea. This study was conducted from 2008 to 2009 to determine the exposure levels of polycyclic aromatic hydrocarbons and nicotine in the Korean general population. The study population consisted of 4702 adult subjects from 196 sampling locations including coastal, rural, and urban areas. The urinary levels of 1-hydroxypyrene, 2-naphthol, and cotinine were measured for exposure of polycyclic aromatic hydrocarbons and nicotine. The geometric means of the urinary 1-hydroxypyrene, 2-naphthol and cotinine concentrations in the Korean general population were 0.15 μg/L (95% confidence interval (CI): 0.13-0.17), 3.84 μg/L (95% CI: 3.57-4.11) and 47.42 μg/L (95% CI: 40.52-54.32) respectively. When these values were compared with reference ranges for the United States and Germany, the levels of 1-hydroxypyrene, 2-naphthol, and cotinine were very similar for Korea and Germany, however, these levels were slightly lower in the United States. This study is the first nationwide survey of exposure to polycyclic aromatic hydrocarbons and nicotine in Korea and provides a background reference range for exposure to polycyclic aromatic hydrocarbons and nicotine in the Korean general population.

Studying the effectiveness of activated carbon R95 respirators in reducing the inhalation of combustion by-products in Hanoi, Vietnam: a demonstration study

BACKGROUND

Urban air pollution is an increasing health problem, particularly in Asia, where the combustion of fossil fuels has increased rapidly as a result of industrialization and socio-economic development. The adverse health impacts of urban air pollution are well established, but less is known about effective intervention strategies. In this demonstration study we set out to establish methods to assess whether wearing an R95 activated carbon respirator could reduce intake of polycyclic aromatic hydrocarbons (PAH) in street workers in Hanoi, Vietnam.

METHODS

In this demonstration study we performed a cross-over study in which non-smoking participants that worked at least 4 hours per day on the street in Hanoi were randomly allocated to specific respirator wearing sequences for a duration of 2 weeks. Urines were collected after each period, i.e., twice per week, at the end of the working day to measure hydroxy PAHs (OH-PAH) using gas chromatography/high resolution mass spectrometry. The primary endpoint was the urinary concentration of 1-hydroxypyrene (1-OHP).

RESULTS

Forty-four participants (54.5% male, median age 40 years) were enrolled with the majority being motorbike taxi drivers (38.6%) or street vendors (34.1%). The baseline creatinine corrected urinary level for 1-OHP was much higher than other international comparisons: 1020 ng/g creatinine (IQR: 604-1551). Wearing a R95 mask had no significant effect on 1-OHP levels: estimated multiplicative effect 1.0 (95% CI: 0.92-1.09) or other OH-PAHs, except 1-hydroxynaphthalene (1-OHN): 0.86 (95% CI: 0.11-0.96).

CONCLUSIONS

High levels of urine OH-PAHs were found in Hanoi street workers. No effect was seen on urine OH-PAH levels by wearing R95 particulate respirators in an area of high urban air pollution, except for 1-OHN. A lack of effect may be de to gaseous phase PAHs that were not filtered efficiently by the respirator. The high levels of urinary OH-PAHs found, urges for effective interventions.

TRIAL REGISTRATION

ISRCTN74390617 (date of assignation: 04/08/2009).

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.

Urinary biomarkers of occupational jet fuel exposure among Air Force personnel

There is a potential for widespread occupational exposure to jet fuel among military and civilian personnel. Urinary metabolites of naphthalene have been suggested for use as short-term biomarkers of exposure to jet fuel (jet propulsion fuel 8 (JP8)). In this study, urinary biomarkers of JP8 were evaluated among US Air Force personnel. Personnel (n=24) were divided a priori into high, moderate, and low exposure groups. Pre- and post-shift urine samples were collected from each worker over three workdays and analyzed for metabolites of naphthalene (1- and 2-naphthol). Questionnaires and breathing-zone naphthalene samples were collected from each worker during the same workdays. Linear mixed-effects models were used to evaluate the exposure data. Post-shift levels of 1- and 2-naphthol varied significantly by a priori exposure group (levels in high group>moderate group>low group), and breathing-zone naphthalene was a significant predictor of post-shift levels of 1- and 2-naphthol, indicating that for every unit increase in breathing-zone naphthalene, there was an increase in naphthol levels. These results indicate that post-shift levels of urinary 1- and 2-naphthol reflect JP8 exposure during the work-shift and may be useful surrogates of JP8 exposure. Among the high exposed workers, significant job-related predictors of post-shift levels of 1- and 2-naphthol included entering the fuel tank, repairing leaks, direct skin contact with JP8, and not wearing gloves during the work-shift. The job-related predictors of 1- and 2-naphthol emphasize the importance of reducing inhalation and dermal exposure through the use of personal protective equipment while working in an environment with JP8.

Repeated measurements for assessment of urinary 2-naphthol levels in individuals exposed to polycyclic aromatic hydrocarbons

A repeated measurement cohort study was conducted to determine whether 2-napthol can be a suitable biomarker for evaluating the magnitude of exposure to PAHs from coke oven emissions. Time-course patterns of urinary 2-naphthol levels in coke-oven workers were examined. Also, the correlation between urinary 2-naphthol levels and PAHs from personal breathing zone samples was analyzed while examining and adjusting possible confounding factors, such as smoking alcohol consumption, and age of human subjects. A total of 8 spot urine samples were collected from each high-exposure group (topside-oven workers, n = 17) and low-exposure group (side-oven workers, n = 25) during the whole working cycle, which consists of six consecutive working days followed by 2 days off. Personal breathing zone samples were collected to quantify PAH intake. A questionnaire was distributed and collected from each worker for assessment of demographic parameters. Our results confirmed that the topside-oven area contained significantly higher PAH levels than the side-oven area. Urinary 2-naphthol levels correlated with the levels of PAH species, including pyrene, benzo[k]fluoranthene, benezo[g,h,i]pyrene, naphthalene, phenanthrene, anthracene, indeno[1,2,3-cd]pyrene, benzo[k]fluoranthene, and total PAHs. During the working cycle, urinary 2-naphthol levels remained stable at around 46-97 ng/mg creatinine during the working days and dramatically increased during the off days. After stratification of data based on smoking status, smokers had significantly higher urinary 2-naphthol levels than non-smokers, and 2-naphthol levels positively correlated with smoking status. Coke-oven emissions are a source of exposure to naphthalene. Also, smoking is a significant source of exposure to naphthalene and served as a confounder factor. Due to its abundance, positive association with total PAHs and certain carcinogenic PAH compounds, and slower elimination kinetics, urinary 2-naphthol may have the potential to serve as a biomarker for PAH exposure, when smoking status is carefully adjusted.

[Using HPLC-MS/MS method to analyze monohydroxy metabolites of PAHs in urine]

OBJECTIVE

To establish a HPLC-MS/MS method for the simultaneous determination of 4 monohydroxy metabolites of polycyclic aromatic hydrocarbons (PAHs) in urine, including 1-naphthol, 2-naphthol, 3-phenanthrol and 1-pyrenol).

METHODS

After being treated by enzymatic hydrolysis, urine samples were purified by liquid-liquid extraction, evaporated under nitrogen to constant volume and examined by HPLC-MS/MS. Target compounds were quantified by internal standard calibration curve.

RESULTS

The reproducibility and precision were improved by internal standard calibration. The recovery of four target compounds were in the range of 89.7%-103.0%. The precision of intra- and inter-batch was 1.0%-4.2% and 1.8%-5.8% respectively. The limits of quantification was 0.2 microg/L for 1-naphthol, 2-naphthol and 1-pyrenol and the limits of quantification was 0.1 microg/L for 3-phenanthrol.

CONCLUSION

The sensitivity, reproducibility and recovery of HPLC-MS/MS method were good for the analysis of 1-naphthol, 2-naphthol, 3-phenanthrol and 1-pyrenol in the urine of people on occupational and nonoccupational exposure to PAHs.

Reproductive hormones in relation to polycyclic aromatic hydrocarbon (PAH) metabolites among non-occupational exposure of males

A limited number of studies have suggested that exposure to PAHs may affect reproductive hormones. Subjects (n=642) in this study were from the affiliated hospitals of Nanjing Medical University. Individual exposures to PAHs were measured as spot urinary concentrations of four PAH metabolites, including 1-naphthol (1-N), 2-naphthol (2-N), 2-hydroxyfluorene (2-OF) and 1-hydroxypyrene (1-OP), which were adjusted by urinary creatinine (CR). Blood samples were collected to measure serum levels of reproductive hormones, including follicle-stimulating hormone (FSH), luteotrophic hormone (LH), estradiol (E2), testosterone (T) and prolactin (PRL). All of the subjects had detectable levels of the four metabolites of PAHs in their urine samples. The median concentrations of 1-N, 2-N, 2-OF and 1-OP were 2.440, 4.176, 2.843 and 1.148 microg/g of CR. There were significant P-values between increased CR-adjusted 1-N tertiles and E2 concentration, 2-OF tertiles and LH, FSH level, 1-OP and E2 level. The multivariate linear regression results also showed significant correlation between the levels of serum LH and 1-OP (the adjusting P-value was 0.048), but no correlations were found between other hormones and the level of PAH metabolites. These observed correlations between levels of hydroxy-PAH and some altered hormones indicated slight endocrine effects on adult men with PAH exposure.

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.

Utility of urinary 1-naphthol and 2-naphthol levels to assess environmental carbaryl and naphthalene exposure in an epidemiology study

We recently reported associations between urinary 1-naphthol (1N) levels and several intermediate measures of male reproductive health, namely sperm motility, serum testosterone levels, and sperm DNA damage. However, because 1N is a major urinary metabolite of both naphthalene and the insecticide carbaryl, exposure misclassification stemming from differences in exposure source was probable and interpretation of the results was limited. As naphthalene, but not carbaryl, is also metabolized to 2-naphthol (2N), the relationship of urinary 1N to 2N within an individual may give information about source of 1N. Utilizing data from two previous studies that measured both 1N and 2N in urine of men exposed to either carbaryl or naphthalene, the present study employed several methods to differentiate urinary 1N arising from exposures to carbaryl and naphthalene among men in the reproductive health study. When re-evaluating the reproductive health data, techniques for identifying 1N source involved exploring interaction terms, stratifying the data set based on 1N/2N ratios, and performing an exposure calibration using a linear 1N to 2N relationship from a study of workers exposed to naphthalene in jet fuel. Despite some inconsistencies between the methods used to distinguish 1N source, we found that 1N from carbaryl exposure is likely responsible for the previously observed association between 1N and sperm motility, whereas 1N from naphthalene exposure is likely accountable for the association between 1N and sperm DNA damage. We demonstrate that studies of health effects associated with carbaryl should utilize a 1N/2N ratio to identify subgroups in which carbaryl is the primary source of 1N. Conversely, studies of naphthalene-related outcomes may utilize 2N levels to estimate exposure.

[Urinary 1-naphthol in the general population of Umbria]

INTRODUCTION

Naphthalene, the most volatile polycyclic aromatic hydrocarbon (PAH), was recently classified as possible human carcinogen by International Agencies for Research on Cancer Humans may be exposed to naphthalene from a wide variety of sources, including occupation, environment, personal habits. We assessed urinary excretion of 1-naphthol (1-NAF), biomarker of naphthalene exposure, in non-occupationally exposed subjects.

MATERIALS AND METHODS

Urinary 1-NAF, 1-hydroxypyrene (1-OHP), biomarker of exposure to pyrene and cotinine, biomarker of smoking habits, were measured in 104 adults (53 men, 51 women).

RESULTS

1-NAF concentrations overlapped in males and females (median: men 0.35 Microg/g creat; women: 0.46 microg/g creat). Median concentration of 1-NAF was 6-fold higher in smokers compared to nonsmokers (respectively, 7.7 microg/g creatinine vs 1.3 microg/g creatinine). Between smokers, urinary cotinine was positively correlated to 1-naphthol (rho: 0.69; p < 0.01) and 1-OHP (rho: 0.53; p < 0.01). Higher 1-OHP concentrations were found in smokers (median: smokers 0.16 microg/g creatinine, not-smokers 0.05 microg/g creatinine;).

CONCLUSIONS

In our study population, we found that 1-NAF excretion is much higher as compared to 1-OHP excretion. This is due to the ubiquitous presence of naphthalene in the environment. Smoking considerably increase the exposure to naftalene.

Thyroid hormones in relation to urinary metabolites of non-persistent insecticides in men of reproductive age

Human exposure to contemporary-use insecticides is widespread, but effects of exposure on human endocrine function have gone largely untested to date. Samples of urine and blood were collected concurrently from 322 adult men between the years 2000 and 2003. Urine samples were analyzed for 3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos-methyl, and 1-napththol (1N), a metabolite of carbaryl and naphthalene. Serum samples were analyzed for free T(4), total T(3), and thyroid stimulating hormone (TSH). There was an association between TCPY and TSH, where an interquartile range (IQR) increase in TCPY was associated with a 9% (95% confidence interval 0-18%) increase in TSH. There was also a suggestive inverse association between TCPY and free T(4). There were no associations between 1N and thyroid hormones. Environmental exposure to chlorpyrifos, chlorpyrifos-methyl, or its metabolite TCPY may be associated with altered thyroid function in human males.

Dermal exposure to jet fuel JP-8 significantly contributes to the production of urinary naphthols in fuel-cell maintenance workers

Jet propulsion fuel 8 (JP-8) is the major jet fuel used worldwide and has been recognized as a major source of chemical exposure, both inhalation and dermal, for fuel-cell maintenance workers. We investigated the contributions of dermal and inhalation exposure to JP-8 to the total body dose of U.S. Air Force fuel-cell maintenance workers using naphthalene as a surrogate for JP-8 exposure. Dermal, breathing zone, and exhaled breath measurements of naphthalene were obtained using tape-strip sampling, passive monitoring, and glass bulbs, respectively. Levels of urinary 1- and 2-naphthols were determined in urine samples and used as biomarkers of JP-8 exposure. Multiple linear regression analyses were conducted to investigate the relative contributions of dermal and inhalation exposure to JP-8, and demographic and work-related covariates, to the levels of urinary naphthols. Our results show that both inhalation exposure and smoking significantly contributed to urinary 1-naphthol levels. The contribution of dermal exposure was significantly associated with levels of urinary 2-naphthol but not with urinary 1-naphthol among fuel-cell maintenance workers who wore supplied-air respirators. We conclude that dermal exposure to JP-8 significantly contributes to the systemic dose and affects the levels of urinary naphthalene metabolites. Future work on dermal xenobiotic metabolism and toxicokinetic studies are warranted in order to gain additional knowledge on naphthalene metabolism in the skin and the contribution to systemic exposure.

Exposure to Nonpersistent Insecticides and Male Reproductive Hormones

BACKGROUND

Urinary metabolites of several nonpersistent insecticides have been measured in a high percentage of men in the general population, suggesting widespread environmental exposures to these compounds. The present study explored the association of urinary concentrations of 3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos-methyl, and 1-naphthol (1N), a metabolite of carbaryl and naphthalene, with serum reproductive hormone levels in adult men.

METHODS

Subjects (n = 268) were the male partners in couples presenting to a Massachusetts infertility clinic in years 2000 through 2003. TCPY and 1N were measured in a spot urine sample from each subject and adjusted for dilution using specific gravity. Reproductive hormones (follicle-stimulating hormone, leuteinizing hormone, inhibin B, testosterone, and sex hormone-binding globulin) were measured in serum collected from subjects during the same clinic visit.

RESULTS

Multiple linear regression models showed an inverse association between TCPY and testosterone concentration. An interquartile range (IQR) increase in TCPY was associated with a decline of 25 ng/dL (95% confidence interval = -40 to -10) in testosterone concentration. The association appeared to be dose-dependent when exposure was divided into quintiles. The highest TCPY quintile was associated with a testosterone decline of 83 ng/dL (-128 to -39) compared with the lowest TCPY quintile. We also found inverse associations between TCPY and free androgen index and between 1N and testosterone, and suggestive inverse associations between TCPY and leuteinizing hormone and between 1N and free androgen index.

CONCLUSION

In adult men, TCPY and 1N were associated with reduced testosterone levels. On a population level, these reductions are of potential public health importance because of widespread exposure to these nonpersistent insecticides.

Determination of dihydroxynaphthalenes in human urine by gas chromatography-mass spectrometry

A gas chromatography-mass spectrometry (GC-MS) method was developed for measuring 1,2-dihydroxynaphthalene (1,2-DHN) and 1,4-dihydroxynaphthalene (1,4-DHN) in urine. The method involves enzymatic digestion of urinary conjugates to release the DHNs which were then analyzed as trimethylsilyl derivatives by GC-MS. For 1,2-DHN and 1,4-DHN, respectively, the assay limits of detection were 0.21 and 0.15 microg/l, the assay limits of quantitation were 0.69 and 0.44 microg/l, and the coefficients of variation were 14.7 and 10.9%. This method was successfully applied to determine urinary levels of 1,2-DHN and 1,4-DHN in coke workers (14 top workers and 13 side-bottom workers) and 21 matching control workers from the steel industry of northern China. The geometric mean (GM) levels of 1,2-DHN were approximately 100 and 30 times higher than those of 1,4-DHN in exposed and control subjects, respectively. The GM levels 1,2-DHN and 1,4-DHN were significantly higher for coke workers (1,2-DHN: top workers--552 microg/l, side-bottom workers--260 microg/l; 1,4-DHN: top workers--3.42 microg/l, side-bottom workers--3.56 microg/l) than for controls (1,2-DHN: 38.8 microg/l; 1,4-DHN: 1.21 microg/l) (p<or=0.0031). In each exposure category, levels of the DHNs were marginally greater in smokers than in nonsmokers (p=0.0646). Strong correlations were observed among 1,2-DHN and 1,4-DHN and previously measured urinary levels of naphthalene, 1-hydroxynaphthalene, and 2-hydroxynaphthalene in these subjects (rs>or=0.623; p<0.0001). Also, levels of 1,2-DHN were significantly correlated with those of serum albumin adducts of l,2-naphthoquinone (rs=0.492, p=0.0004). These results indicate that 1,2- and 1,4-DHN are good biomarkers for assessment of naphthalene exposure in coke workers. Since the DHNs are precursors of the naphthoquinones, which have been implicated as toxic products of naphthalene metabolism, measurements of urinary DHNs may have toxicological significance.

Evaluation of immuno- and reproductive toxicities and association between immunotoxicological and genotoxicological parameters in waste incineration workers

In this study, we investigated immunotoxicity levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin in 31 waste incineration workers and in 84 control subjects, and evaluated the association between immunological and genotoxicological parameters. DNA damage in mononuclear and polynuclear lymphocytes, and the level of the urinary metabolites, 1-OHP and 2-naphthol, were evaluated in both waste incineration workers and control subjects. Significant differences were detected in these values between exposed and control groups. Number of sperms was lower in the waste incineration workers than in the control subjects, as was the percentage of motile sperms, but a significant difference existed only in the number of sperms (p=0.05). DNA damage in the spermatozoa of waste incineration workers and control subjects measured 1.40+/-0.08 and 1.26+/-0.03, respectively (p=0.001). Specific surface antigens of peripheral lymphocytes, namely, CD3, CD4, CD8, CD19, and CD69 were used to measure immune status in waste incineration workers and control subjects. There was no significant difference in T- and B-cell profiles showed between waste incineration workers and control subjects (p=0.684 and 0.157). In addition, the ratio of T helper cells to T cytotoxic cells was also not remarkably different between groups (p=0.174). However, T-cell activation was found to be significantly higher in the waste incineration workers than in the control subjects (p=0.001), although B-cell activation did not exhibit this trend. The levels of two cytokines (IL-4 an INF-gamma) and four immunoglobulins (IgA, IgE, IgG, and IgM) were also measured in the experimental population. All immunoglobulin types were found in lower amounts in the waste incineration workers, but this diaparity was not significant one. In addition, the levels of two cytokines, IL-4 and INF-gamma, were also found to be lower in the waste incineration workers than in the control subjects, and only in IL-4 was a significant difference determined to exist.

Effects of air pollutants on childhood asthma

Epidemiologic studies have suggested the association between environmental exposure to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) and the increased risk of incurring asthma. Yet there is little data regarding the relationship between personal exposure to air pollution and the incidence of asthma in children. This study was designed to evaluate the effect of exposure to air pollution on children with asthma by using exposure biomarkers. We assessed the exposure level to VOCs by measuring urinary concentrations of hippuric acid and muconic acid, and PAHs by 1-OH pyrene and 2-naphthol in 30 children with asthma and 30 children without asthma (control). The mean level of hippuric acid was 0.158 +/- 0.169 micromol/mol creatinine in the asthma group and 0.148 +/- 0.249 micromol/mol creatinine in the control group, with no statistical significance noted (p=0.30). The mean concentration of muconic acid was higher in the asthma group than in the control group (7.630 +/- 8.915 micromol/mol creatinine vs. 3.390 +/- 4.526 micromol/mol creatinine p=0.01). The mean level of urinary 1-OHP was higher in the asthma group (0.430 +/- 0.343 micromol/mol creatinine) than the control group (0.239 +/- 0.175 micromol/mol creatinine), which was statistically significant (p=0.03). There was no difference in the mean concentration of 2-NAP between the two groups (9.864 +/- 10.037 micromol/mol in the asthma group vs. 9.157 +/- 9.640 micromol/mol in the control group, p=0.96). In conclusion, this study suggests that VOCs and PAHs have some role in asthma.

Effect of ‘PC Game Room’ use and polycyclic aromatic hydrocarbon exposure on plasma testosterone concentrations in young male Koreans

BACKGROUND

'PC Game Rooms' were first popularized in Korea, although the concept is now becoming popular worldwide. PC Game Rooms provide users with high-performance PC connected to the high-speed internet, and access to computer games. However, PC Game Room users are exposed to various hazardous agents such as cigarette smoke in a confined environment, and thus it is likely that excessive PC Game Room use involves abnormal exposure to polycyclic aromatic hydrocarbons (PAH) as well as being associated with disturbed sleep or circadian rhythm.

METHODS

In this cross-sectional study, the exposure to PAH was evaluated by measuring urinary 1-hydroxypyrene (1-OHP) and 2-naphthol. The correlations between PC Game Room use and PAH exposure and plasma testosterone and LH levels were analysed in 208 young male Koreans.

RESULTS

Urinary 1-OHP concentrations increased (P = 0.0001) and plasma testosterone levels decreased (P = 0.0153) significantly with increased duration of PC Game Room use. Correlation analysis showed that plasma testosterone concentrations were significantly negatively correlated with urinary 1-OHP (r = -0.22, P = 0.0012) and 2-naphthol (r = -0.15, P = 0.0308) concentrations. Moreover, these associations persisted after adjusting for other independent variables. However, the duration of PC Game Room use itself was not found to be an independent significant determinant of plasma testosterone level. Rather, PC Game Room use increased PAH exposure, which decreased plasma testosterone level. The younger age group (15-19 years) showed a more prominent decrease in plasma testosterone concentrations with increasing duration of PC Game Room use than the older age group (20-24 years) (r2 = 0.355, P = 0.0301 versus r2 = 0.213, P = 0.0001).

CONCLUSIONS

These results imply that the excessive use of PC Game Rooms is related to an adverse impact on sex hormonal status in young male Koreans via PAH exposure. This effect was more prominent in the younger age group.

Glucuronidation of 1-naphthol and excretion into the vein in perfused rat kidney

UDP-glucuronosyltransferase is expressed in the proximal convoluted tubular cells of rat kidney. Kidney perfusion with a Krebs-Henseleit buffer containing 1-naphthol was performed to estimate the dynamics and disposition of the glucuronide conjugate formed in the epithelial cells of the renal tubules. When 1-naphthol was injected into the renal artery, and the perfusate from the renal vein was returned to a reservoir and recirculated through the kidney preparation (recirculating perfusion), most of the 1-napthol was immediately excreted into the vein as a glucuronide conjugate and its concentration increased rapidly. In contrast, the 1-napthol glucuronide appeared more slowly in the urine. 1-Naphthol was also injected during the initial 5 min of perfusion under single-pass perfusion conditions (single-pass perfusion) in situ, and the metabolite and parent compound in the venous perfusate and in urine were assayed. Under this condition, most of the 1-naphthol glucuronide was excreted into the renal vein, and not urine. Phenol UDP-glucuronosyltransferase was highly induced in the rat kidney by beta-naphthoflavone treatment. Moreover, the amount of 1-naphthol glucuronide excreted in the renal vein was increased 2.7-fold in the perfused kidney of beta-naphthoflavone-treated rats, but the amount in the urine was not significantly increased under singlepass perfusion conditions. These results indicate that the kidney can glucuronidate phenolic xenobiotics in epithelial cells of the tubules and excrete the resultant glucuronide into the renal vein.

The relationship of urinary metabolites of carbaryl/naphthalene and chlorpyrifos with human semen quality

Most of the general population is exposed to carbaryl and other contemporary-use insecticides at low levels. Studies of laboratory animals, in addition to limited human data, show an association between carbaryl exposure and decreased semen quality. In the present study we explored whether environmental exposures to 1-naphthol (1N), a metabolite of carbaryl and naphthalene, and 3,5,6-trichloro-2-pyridinol (TCPY), a metabolite of chlorpyrifos and chlorpyrifos-methyl, are associated with decreased semen quality in humans. Subjects (n=272) were recruited through a Massachusetts infertility clinic. Individual exposures were measured as spot urinary concentrations of 1N and TCPY adjusted using specific gravity. Semen quality was assessed as sperm concentration, percent motile sperm, and percent sperm with normal morphology, along with sperm motion parameters (straight-line velocity, curvilinear velocity, and linearity). Median TCPY and 1N concentrations were 3.22 and 3.19microg/L, respectively. For increasing 1N tertiles, adjusted odds ratios (ORs) were significantly elevated for below-reference sperm concentration (OR for low, medium, and high tertiles = 1.0, 4.2, 4.2, respectively; p-value for trend =0.01) and percent motile sperm (1.0, 2.5, 2.4; p-value for trend = 0.01). The sperm motion parameter most strongly associated with 1N was straight-line velocity. There were suggestive, borderline-significant associations for TCPY with sperm concentration and motility, whereas sperm morphology was weakly and nonsignificantly associated with both TCPY and 1N. The observed associations between altered semen quality and 1N are consistent with previous studies of carbaryl exposure, although suggestive associations with TCPY are difficult to interpret because human and animal data are currently limited.

Simultaneous determination of 1- and 2-naphthol in human urine using on-line clean-up column-switching liquid chromatography-fluorescence detection

We developed a new 3-D HPLC method for on-line clean-up and simultaneous quantification of two important naphthalene metabolites, 1-naphthol and 2-naphthol, in human urine. Except an enzymatic hydrolysis no further sample pre-treatment is necessary. The metabolites are stripped from urinary matrix by on-line extraction on a restricted access material pre-column (RAM RP-8), transferred in backflush mode onto a silica-based CN-(cyano)phase column for further purification from interfering substances. By another successive column switching step both analytes are transferred with a minimum of overlapping interferences onto a C12 bonded reversed phase column with trimethylsilyl endcapping where the final separation is carried out. The entire arrangement is software controlled. Eluting analytes are quantified by fluorescence detection (227/430 nm) after an external calibration. Within a total run time of 40 min we can selectively quantify both naphthols with detection limits in the lower ppb range (1.5 and 0.5 microg/l for 1- and 2-naphthol, respectively) with excellent reliability (ensured by precision, accuracy, matrix-independency and FIOH quality assurance program participation). First results on a collective of 53 occupationally non exposed subjects showed mean levels of 11.0 microg/l (1-naphthol) and 12.9 microg/l (2-naphthol). Among smokers (n=21) a significantly elevated mean level of urinary naphthols was determined (1-naphthol: 19.2 microg/l and 2-naphthol: 23.7 microg/l) in comparison to non smokers (n=32; 1-naphthol: 5.6 microg/l, 2-naphthol: 5.6 microg/l).

Evaluation of biological monitoring markers using genomic and proteomic analysis for automobile emission inspectors and waste incinerating workers exposed to polycyclic aromatic hydrocarbons or 2,3,7,8,-tetracholrodedibenzo-p-dioxins

In this study, we investigated the effects of PAHs and dioxin on mRNA and plasma protein expression using genomic and proteomic analysis for automobile emission inspectors and waste incineration workers. About 54 workers from automobile emission inspection offices, 31 workers from waste incinerating company and 84 unexposed healthy subjects were enrolled in this study. Urine and air samples were collected and analyzed by HPLC and GC/MS. Comet assays were carried out to evaluate any DNA damage in mononuclear and polynuclear cells. A significant difference in Olive tail moments in mononuclear cells was observed between exposed and control subjects (P < 0.0001). To examine the differences of the gene expression profile in automobile emission inspectors and waste incineration workers, radioactive complementary DNA microarrays were used to evaluate changes in the expression of 1,152 total genes. The gene expression profiles showed that 11 genes were up-regulated and 4 genes were down-regulated in waste incinerating workers as compared with controls. Plasma proteins were analyzed by 2-dimentional electrophoresis with pH 3-10 NL IPG Dry strip. The protein expression profiles showed that 8 proteins were up- regulated and 1 protein, haptoglobin, was down- regulated in automobile emission inspectors and waste incineration workers. Serum paraoxonase/ arylesterase was found only in the plasma of waste incineration workers. The expression of genes and proteins involved in oxidative stress were up-regulated in both automobile emission inspectors and waste incineration workers. Several proteins, such as transthyrethin, sarcolectin and haptoglobin, that were highly up- or down-regulated, could serve as biological monitoring markers for future study.

Dose-dependent production of urinary naphthols among workers exposed to jet fuel (JP-8)

BACKGROUND

Jet propulsion fuel-8 (JP-8) is one of the largest sources of chemical exposures among Air Force personnel. Urinary naphthols have been suggested as useful biomarkers of exposure to JP-8.

METHODS

Multivariate linear regression models were applied to evaluate the effects of environmental and work-related factors upon production of urinary naphthols among 323 Air Force personnel.

RESULTS

Naphthalene exposure, smoking status, and their interaction, plus self-reported skin irritation explained about two-thirds of the variation in naphthol levels. The exposure-smoking interaction was consistent with induction by smoking of one or more steps in the metabolism of naphthalene and naphthalene-1,2-oxide (NapO). A supralinear dose-response relationship was observed between urinary naphthols and naphthalene exposure.

CONCLUSIONS

Urinary naphthols were associated with specific sources of exposure to JP-8, arising from both inhalation and dermal contact. Smokers and nonsmokers metabolized naphthalene at different rates, consistent with induction of at least two metabolic pathways by smoking.

Urinary biomarkers in charcoal workers exposed to wood smoke in Bahia State, Brazil

Charcoal is an important source of energy for domestic and industrial use in many countries. Brazil is the largest producer of charcoal in the world, with approximately 350,000 workers linked to the production and transportation of charcoal. To evaluate the occupational exposure to wood smoke and potential genotoxic effects on workers in charcoal production, we studied urinary mutagenicity in Salmonella YG1041 +S9 and urinary levels of 2-naphthol and 1-pyrenol in 154 workers of northeastern Bahia. Workers were classified into three categories according to their working location, and information about socio-demographic data, diet, alcohol consumption, and smoking was obtained using a standard questionnaire. Spot urine samples were collected to evaluate urinary mutagenicity and urinary metabolites. Urinary mutagenicity increased significantly with exposure to wood smoke and was modified by smoking. The prevalence odds ratio was 5.31, and the 95% confidence interval was 1.85; 15.27 for urinary mutagenicity in the highly exposed group relative to the nonexposed group. The levels of urinary metabolites increased monotonically with wood smoke exposure and were associated with the GSTM1 null genotype, which was determined previously. The prevalence odds ratio (95% confidence interval) for higher levels of 2-naphtol among the highly exposed was 17.13 (6.91; 42.44) and for 1-hydroxyprene 11.55 (5.32; 25.08) when compared with nonexposed workers. Urinary 2-naphthol was the most sensitive indicator of wood smoke exposure. This is the first reported measurement of internal exposure to wood smoke among charcoal workers, and the results showed that these workers receive a systemic exposure to genotoxic compounds.

Effects of genetic polymorphisms in metabolic enzymes on the relationships between 8-hydroxydeoxyguanosine levels in human leukocytes and urinary 1-hydroxypyrene and 2-naphthol concentrations

This study was designed to investigate the relationship between environmental exposure to polycyclic aromatic hydrocarbons (PAHs) and oxidative stress, and to evaluate the effects of cigarette smoking and the genetic polymorphisms of CYP1A1, CYP2E1, GSTM1, NAT2 and UGT1A6 on the relationship. The subjects of this study were 105 healthy Korean males without occupational exposure to PAHs. The 8-hydroxydeoxyguanosine (8-OHdG) level in leukocytes, and urinary 1-hydroxypyrene (1-OHP) and 2-naphthol concentrations, were measured by high-performance liquid chromatography. Genetic polymorphisms of CYP1A1, CYP2E1, GSTM1, NAT2 and UGT1A6 were identified by PCR and PCR-RFLP methods. The 8-OHdG level showed a significant correlation with the 1-OHP concentration in all subjects (p<.001) and in smokers (p<.01), and with the 2-naphthol level in non-smokers (p<.01). The 8-OHdG level was significantly higher in smoking rapid acetylators than in smoking slow or intermediate acetylators, and in individuals with the UGT1A6 wild-type than in those with the UGT1A6 mutant genotype. Significant positive correlations between 8-OHdG and 1-OHP concentrations were found in subjects with every genotype of the CYP1A1 and CYP2E1 genes, with the GSTM1 null-type, with the NAT2 genotype of a rapid acetylator, and with the UGT1A6 wild-type, respectively. The urinary 2-naphthol level significantly correlated with the 8-OHdG level only in subjects with the GSTM1 null-type. In conclusion, there is a significant correlation between the 8-OHdG level in leukocytes and the urinary 1-OHP concentration in the population not occupationally exposed to PAHs. This relationship is affected by genetic polymorphisms in PAH metabolic enzymes.

Pilot study on the naphthalene exposure of German adults and children by means of urinary 1- and 2-naphthol levels

Concentrations of 1- and 2-naphthol were measured in urine of 72 adults and 35 young children from Germany to assess the internal exposure to naphthalene of the general population. Naphthols could be detected in more than 90% of the urine samples. Levels of naphthols (sum of 1- and 2-naphthol) were 4-fold higher in smokers (median: 37.6 microg/g creatinine) compared to non-smoking adults (8.2 microg/g creatinine). On a creatinine basis young children had slightly lower naphthol levels in urine compared with adults (7.5 microg/g creatinine). Preliminary reference values for the sum of 1- and 2- naphthol in urine as means of the 95th percentile are proposed: 41.2 microg/g creatinine (non-smoking adults) and 23.5 microg/g creatinine (young children). It is concluded that 1- and 2-naphthol levels in urine are suitable for human biomonitoring of the naphthalene exposure in environmental medicine.

Urinary biomarkers of exposure to jet fuel (JP-8)

Benzene, naphthalene, and 1- and 2-naphthol were measured in urine samples obtained from 322 U.S. Air Force personnel categorized a priori as likely to have low, moderate, or high exposure to jet fuel [jet propulsion fuel-8 (JP-8)]. In postexposure samples, levels of these analytes in the high-exposure group were 3- to 29-fold greater than in the low-exposure group and 2- to 12-fold greater than in the moderate-exposure group. Heavy exposure to JP-8 contributed roughly the same amount of benzene and more than three times the amount of naphthalene compared with cigarette smoking. Strong correlations were observed among postexposure levels of naphthalene-based biomarkers in urine and naphthalene in air and breath. We conclude that urinary naphthalene and the naphthols can serve as biomarkers of exposure to jet fuel. Of these, the naphthols are probably more useful because of their greater abundance and slower elimination kinetics.

DNA damage in T- and B-lymphocytes and granulocytes in emission inspection and incineration workers exposed to polycyclic aromatic hydrocarbons

In this study, we investigated by using comet assay the effects of polycyclic aromatic hydrocarbon (PAH) as a major factor on DNA damage of workers exposed to exhaust fumes. Twenty-four workers from three automobile emission inspection companies, 28 workers from a waste incinerating company, and 43 matched, unexposed healthy subjects were enrolled in the study. The mean values of 1-hydroxypyrene (1-OHP) in automobile emission inspection and waste incineration workers were 0.27+/-0.19 and 0.57+/-0.46 micromol/mol creatinine, respectively, and the mean values of 2-naphthol in automobile emission inspectors and waste incineration workers were 4.80+/-4.01 and 8.30+/-4.79 mol/mol creatinine, respectively. Significant difference in urinary metabolites, 1-hydroxypyrene and 2-naphthol was found between smokers and non-smokers in exposed groups and it may be due to the amounts of smoking cigarettes. In T-lymphocytes, DNA damage in control subjects, emission inspection workers and incineration workers were 1.42+/-0.22, 1.41+/-0.22 and 1.76+/-0.27, respectively. DNA damage of B-lymphocytes in the three groups showed the most significant differences of three cell types. The tail moments of the B-lymphocytes of control subjects, emission inspection and incineration workers were 1.40+/-0.27, 2.44+/-0.32 and 2.36+/-0.37, respectively. In granulocytes, DNA damage was also different, the tail moments being 2.72+/-0.59, 3.32+/-0.38 and 2.85+/-0.49, respectively. Although 1-OHP and 2-naphthol levels were statistically increased in smokers in workers exposed to PAHs, exposed smoking and non-smoking workers did not show any significantly difference in terms of Olive tail moments. Our results suggest that PAH causes single strand DNA breakage in human T- and B-lymphocytes, and granulocytes. A comparison of DNA damage in three groups showed that B-lymphocytes are useful target in the biomonitoring of human exposure.

Simultaneous analysis of naphthols, phenanthrols, and 1-hydroxypyrene in urine as biomarkers of polycyclic aromatic hydrocarbon exposure: intraindividual variance in the urinary metabolite excretion profiles caused by intervention with beta-naphthoflavone induction in the rat

Two fluorimetric HPLC methods are described for the quantification of naphthols, phenanthrols and 1-hydroxypyrene (1-OHP) in urine specimens obtained from male Wistar rats exposed to naphthalene, phenanthrene and pyrene. The polycyclic aromatic hydrocarbons (PAHs) were given intraperitoneally, either alone (1.0 mmol/kg body weight) or as an equimolar mixture (0.33 mmol/kg), using the same dosages for repeated treatments on week 1 and week 2. Between these treatments, PAH-metabolizing activities encoded by aryl hydrocarbon (Ah) receptor-controlled genes were induced in the rats with beta-naphthoflavone (betaNF). Chromatographic separation of five phenanthrols (1-, 2-, 3-, 4-, and 9-isomers) was accomplished using two different RP C-18 columns. Despite selective detection (programmable wavelengths), the quantification limits in the urine ranged widely: 1-OHP (0.18 microg/l) <phenanthrols (0.34-0.45 microg/l) <2-naphthol (1.5 microg/l) <1-naphthol (4 micro g/l). The relative standard deviation of the methods was good, as also was the reproducibility. The molar fraction of the dose excreted in 24-h urine as naphthols (<or=4.0%), phenanthrols (<or=1.1%), and 1-OHP (<or=2.4%) was low. Urinary disposition increased differentially in betaNF-induced rats: naphthols, 9-phenanthrol (1- to-2-fold); 2-, 3-, and 4-phenanthrols (4- to 5-fold); 1-phenanthrol and 1-OHP (over 11-fold). The OH-metabolites were analyzed before and after enzymatic hydrolysis (beta-glucuronidase/arylsulfatase). The percentage excreted as a free phenol in urine varied for 1-OHP (2-11%), 1-naphthol (36-51%), 2-naphthol (59-65%), and the phenanthrols (29-94%). 1-Naphthyl- and 1-pyrenyl beta- d-glucuronide served as measures for the completeness of enzymatic hydrolysis. Characteristic differences observed in the urinary disposition of naphthalene, phenanthrene, and pyrene are described, as well as important factors (dose, metabolic capacity, relative urinary output) associated with biomarker validation. This intervention study clarifies intraindividual variation in PAH metabolism and provides useful information for the development of new methods applicable in the biomonitoring of PAH exposure in humans.

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.

Correlation of urinary 1-hydroxypyrene and 2-naphthol with total suspended particulates in ambient air in municipal middle-school students in Korea

The authors investigated Korean municipal middle school students to ascertain whether urinary 1-hydroxypyrene (1-OHP) and 2-naphthol-markers for polycyclic aromatic hydrocarbon (PAH) exposure-reflect PAHs in ambient air. The authors used the beta-ray absorption method, which is an index of ambient-air PAH exposure, to collect total suspended particulate (TSP) data. The authors measured urinary 1-OHP and 2-naphthol concentrations in 137 nonsmoking students in 4 municipal middle schools within 1 km of ambient air monitoring stations. The median concentrations of urinary 1-OHP and 2-naphthol in the study were 0.09 nmole/mol creatinine and 2.19 micromol/mol creatinine, respectively, and the geometric means were 0.10 nmole/mol creatinine and 2.47 micromol/mol creatinine, respectively. Urinary 1-OHP concentration did not correlate significantly with any TSP index. There were significant correlations between urinary 2-naphthol level and the daily mean TSP level calculated for 2 days before survey, for 1 day before survey, and for the day of survey. These data suggest that urinary 2-naphthol may be a good marker for inhalation exposure to PAHs in ambient air.

Effects of genetic polymorphisms of CYP1A1, CYP2E1, GSTM1, and GSTT1 on the urinary levels of 1-hydroxypyrene and 2-naphthol in aircraft maintenance workers

This study was undertaken to investigate the effects of genetic polymorphisms of the cytochrome P450 1A1 (CYP1A1) and 2E1 (CYP2E1), and glutathione S-transferases mu (GSTM1) and theta (GSTT1) on urinary 1-hydroxypyrene and 2-naphthol levels, and to estimate the level of exposure to polycyclic aromatic hydrocarbons (PAHs) in aircraft maintenance workers. In 218 Korean aircraft maintenance workers, the geometric means of urinary 1-hydroxypyrene and 2-naphthol were 0.32 and 3.25 micromol/mol creatinine, respectively. These urinary concentrations were approximately at the upper limit of the general population. Mean urinary 2-naphthol concentrations were significantly different between smokers and non-smokers. CYP1A1 and GSTM1 were statistically significant in analyses on both 1-hydroxypyrene and 2-naphthol levels among smokers. The results suggest that smoking has more profound effects on urinary PAH metabolites than does genetic polymorphisms in this population, and that CYP1A1 and GSTM1 activity might be related to the metabolism of 1-hydroxypyrene and 2-naphthol.