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

Biomarkers for polycyclic aromatic hydrocarbons in human excreta: recent advances in analytical techniques-a review

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that are generated by the incomplete combustion of organic materials. The main anthropogenic sources of PAHs are the combustion of solid fuels for heating purposes, illegal waste incineration, road transport and industries based on fossil fuels. PAHs can easily enter the body because they are present in all elements of the environment, including water, soil, air, and food. Due to their ubiquitous presence, PAHs, may exert a harmful effect on human health. Assessing PAH exposure through biomonitoring mostly involve techniques to measure the concentration of 1-hydroxypyrene in human urine. Nevertheless, through recent progress in analytical techniques, other common metabolites of PAHs in human biospecimens can be detected. A scientific literature search was conducted to determine which hydroxy derivatives of PAHs are markers of PAHs exposure and to reveal the leading sources of these compounds. Techniques for analyzing biological samples to identify OH-PAHs are also discussed. The most frequently determined OH-PAH in human urine is 1-hydroxypyrene, the concentration of which reaches up to a dozen ng/L in urine. Apart from this compound, the most frequently determined biomarkers were naphthalene and fluorene metabolites. The highest concentrations of 1- and 2-hydroxynaphthalene, as well as 2-hydroxyfluorene, are associated with occupational exposure and reach approximately 30 ng/L in urine. High molecular weight PAH metabolites have been identified in only a few studies. To date, PAH metabolites in feces have been analyzed only in animal models for PAH exposure. The most frequently used analytical method is HPLC-FLD. However, compared to liquid chromatography, the LOD for gas chromatography methods is at least one order of magnitude lower. The hydroxy derivatives naphthalene and fluorene may also serve as indicators of PAH exposure.

Evaluation of respiratory function and biomarkers of exposure to mixtures of pollutants in brick-kilns workers from a marginalized urban area in Mexico

Brick-kilns are polluted environments due to the use of low-quality technologies and fuels, which generates black fumes with a large number of pollutants. The objective of this research was to analyze environmental exposure and biomarkers of exposure to polycyclic aromatic hydrocarbons, metals, and respiratory health in brickmakers to assess the baseline state of contamination in a brick-kiln area of San Luis Potosi, Mexico. Lead was quantified in soil and particulate matter of 2.5 μm (PM_2.5) and 10 μm (PM₁₀) in brick-kiln areas. In brickmakers, lead was evaluated in whole blood and 10 hydroxylated metabolites of polycyclic aromatic hydrocarbons were determined in urine. Respiratory health was assessed by spirometry, exhaled breath condensate, and a COPD-PS questionnaire. Data association was performed by Spearman correlation. Environmental concentrations and biomarkers of exposure are presented as medians, for lead, it was 60.4 mg/kg, for PM10, it was 2663.1 μg/m³, and for PM2.5, it was 166.6 μg/m³. For blood lead, it was 1.06 μg/dL, and the summed concentration of OH-PAHs in urine was 16.1 μg/L. Spirometry values were 2.8 ± 0.6 L and 2.9 ± 1.3 L/s FEV1 and FEV 25-75 respectively. The correlation results indicate that the older the age of the workers is and the extensive period they have been working, their lung function is affected the most. The health vulnerability present in these occupational activities is high, so it is necessary to make visible, address these economic activities in Mexico, and apply surveillance systems based on the health of the worker.

Internal exposure levels of polycyclic aromatic hydrocarbons in children and adolescents: a systematic review and meta-analysis

Polycyclic aromatic hydrocarbons (PAHs) are widely found in the environment, and comparing to adults, children are more vulnerable to PAHs exposure. Urinary metabolites of PAHs are used as preferred biomarkers to estimate the PAHs exposure. Systematic review on the internal exposure level of children and adolescents is rare. We aimed to calculate the internal exposure levels of PAHs in children and adolescents and compare the levels of PAHs internal exposure in various children groups. We searched PubMed, OVID, Web of Science, EBSCO, ACS, and four Chinese databases, and all studies examining the urinary concentrations of PAHs in children and adolescent were identified. The total exposure level of 11 PAHs metabolites were pooled. Standard mean difference (SMD) and 95% confidence intervals (CIs) of PAHs urinary concentration were calculated and pooled by RevMan5.3 to compare the exposure levels of different children groups. We found that 1-OHPyr, 2-OHNap, 2-OHFlu, 3-OHPhe, and 4-OHPhe were five PAHs metabolites most commonly studied in existing studies in children, and their total exposure levels were 0.38 ± 0.98, 2.32 ± 4.83, 0.81 ± 1.54, 0.09 ± 0.14, 0.03 ± 0.10 μmol/mol creatinine, respectively. The meta-analysis showed that the levels of 1-OHPyr were higher in higher environmental exposure group (SMD = 0.21, 95% CI = 0.03~0.40), ETS exposure group (SMD = 0.31, 95% CI = 0.08~0.54), and 6~11 years group (SMD = 0.16, 95% CI = 0.09~0.24); the level of 2-OHNap (SMD = 0.27, 95% CI = 0.01~0.53) was higher in higher environmental exposure group; however, the levels of 3-OHPhe (SMD = − 0.34, 95% CI = − 0.57~− 0.12) and 4-OHPhe (SMD = − 0.48, 95% CI = − 0.69~− 0.28) were higher in lower environmental exposure group. The levels of 1-OHPyr (SMD = − 0.01, 95% CI = − 0.11~0.10) and 2-OHNap (SMD = 0.01, 95% CI = − 0.20~0.22) were not statistically different between boys and girls. In conclusions, we found that the internal diversity of PAHs existed in children and adolescents, and the level of 1-OHPyr in children and adolescents was in higher status compared with non-occupational people who do not smoke.

Urinary biomarkers of polycyclic aromatic hydrocarbons in pre- and peri-pubertal girls in Northern California: Predictors of exposure and temporal variability

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs), a class of chemicals produced as combustion by-products, have been associated with endocrine disruption. To understand exposure in children, who have been less studied than adults, we examined PAH metabolite concentrations by demographic characteristics, potential sources of exposure, and variability over time, in a cohort study of pre- and peri-pubertal girls in Northern California.

METHODS

Urinary concentrations of ten PAH metabolites and cotinine were quantified in 431 girls age 6-8 years at baseline. Characteristics obtained from parental interview, physical exam, and linked traffic data were examined as predictors of PAH metabolite concentrations using multivariable linear regression. A subset of girls (n = 100) had repeat measures of PAH metabolites in the second and fourth years of the study. We calculated the intraclass correlation coefficient (ICC), Spearman correlation coefficients, and how well the quartile ranking by a single measurement represented the four-year average PAH biomarker concentration.

RESULTS

Eight PAH metabolites were detected in ≥ 95% of the girls. The most consistent predictors of PAH biomarker concentrations were cotinine concentration, grilled food consumption, and region of residence, with some variation by demographics and season. After adjustment, select PAH metabolite concentrations were higher for Hispanic and Asian girls, and lower among black girls; 2-naphthol concentrations were higher in girls from lower income households. Other than 1-naphthol, there was modest reproducibility over time (ICCs between 0.18 and 0.49) and the concentration from a single spot sample was able to reliably rank exposure into quartiles consistent with the multi-year average.

CONCLUSIONS

These results confirm diet and environmental tobacco smoke exposure as the main sources of PAHs. Controlling for these sources, differences in concentrations still existed by race for specific PAH metabolites and by income for 2-naphthol. The modest temporal variability implies adequate exposure assignment using concentrations from a single sample to define a multi-year exposure timeframe for epidemiologic exposure-response studies.

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.

Urinary polycyclic aromatic hydrocarbon metabolites among 3-year-old children from Krakow, Poland

Polycyclic aromatic hydrocarbons (PAHs) are widespread in the environment and can adversely affect human health. The aim of the present study is to describe the level of PAHs exposure in children living in Kraków, one of the most polluted cities in Poland, and to determine the relationship of urinary biomarkers with environmental PAHsexposure. Urinary monohydroxy metabolites (OH-PAHs) of 20 PAHs were assessed in 218 three-year old children, of which only 10 were present in nearly all the samples: monohydroxy metabolites of naphthalene, fluorene, phenantrene and pyrene. Of the metabolites analyzed, hydroxynaphthalenes were predominant and constituted almost 73% of total excreted OH-PAHs, while 1-OH-PYRene was the least abundant (2.3% of total OH-PAHs). All measured urinary OH-PAHs were statistically significantly correlated with each other (R = 0.165-0.880) but the highest correlation coefficients with other individual OH-PAHs and with total OH-PAHs were observed for 2-OH-FLUOR. Children exposed at home to environmental tobacco smoke (ETS) had higher concentrations of fluorene and pyrene urinary metabolites compared to those without ETS exposure; and those exposed to gas-based appliances used for cooking or heating water had higher levels of fluorene and phenanthrene metabolites than children not exposed. The use of coal, wood or oil for heating was associated with elevated levels of 1-OH-PYRene. Urinary PAHs metabolites only modestly reflect high molecular weight carcinogenic PAHs exposures such as those monitored in air in the present study. None of the measured PAHs metabolites was correlated with airborne PM_2.5 and only two were slightly correlated with measured higher molecular mass airborne PAHs. The average concentrations of these specific metabolites in Polish children were much higher than observed in other pediatric populations living in developed countries. Our findings suggest that to capture various sources of PAHs, in addition to 1-OH-PYRene, biomonitoring of PAHs exposure should include 2-OH-NAP and 2-OH-FLUOR.

Levels and risk factors for urinary metabolites of polycyclic aromatic hydrocarbons in children living in Chongqing, China

AIMS

Since childhood exposure to polycyclic aromatic hydrocarbons (PAHs) have been associated with a variety of adverse health outcomes, the aims of this study were to1) document PAH exposure levels among children in Chongqing, China by measuring urinary concentrations of four PAH metabolites, 1-hydroxypyrene (1-OHPyr), 2-hydroxynaphthalene (2-OHNap), 2-hydroxyfluorine (2-OHFlu) and 9-hydroxyphenanthrene (9-OHPhe), and 2) assess the associations of urinary concentrations of these PAH metabolites with risk factors related to sources of PAHs inhalation and ingestion exposures and with personal attributes such as sex, age, and BMI.

METHODS

The present study is a cross-sectional analysis using data drawn from the third follow up of a longitudinal study. Purposive sampling was used with all students in grades one to four in four schools being eligible to participate. The baseline survey included a total of 1237 students 5.8 to 12.2years of age. At the third follow up survey, 1.5years after the baseline survey, 1230 of the children had a physical exam and provided urine samples. Their parents completed a questionnaire including social-demographic information and possible sources of children's exposure to PAHs. Urine samples were measured for the four OH-PAHs using an HPLC-MS/MS technique. Concentrations were corrected by specific gravity. Linear regression analysis was used to investigate factors related to sources of PAHs exposure.

RESULTS

The urinary concentrations were highest for 9-OHPhe (median at the range of 3661ng/L), followed by 2-OHNap (3189ng/L), 2-OHFlu (1116ng/L), and 1-OHPyr (250ng/L). In multiple linear regressions, being female (P=0.04), school location near a thermal power plant (P=0.02) and higher maternal age at birth (P<0.01) were associated with increased concentrations of urinary 1-OHPyr; no significant associations were found for 2-OHNap; school location near a thermal power plant (P<0.01) and lower family income (P<0.01) were associated with increased concentrations of urinary 2-OHFlu; higher age (P<0.01), school location near a thermal power plant (P=0.01), frequent consumption of smoked foods (P=0.04) and lower family income (P=0.07) were all found to be associated with increased concentrations of 9-OHPhe.

CONCLUSIONS

Urinary concentrations of OH-PAHs, especially 9-OHPhe, were elevated in Chongqing Children compared to children in other countries. Being female, older age, school location near an industrial site, frequent consumption of smoked foods and lower family income were all associated with higher OH-PAHs concentrations. Further cohort studies are needed to confirm the associations between potential exposure sources and children's exposure to PAHs, in order to provide recommendations to reduce exposure.

Predictors of polycyclic aromatic hydrocarbon exposure and internal dose in inner city Baltimore children

Polycyclic aromatic hydrocarbons (PAHs), the by-products of incomplete combustion of organic materials, are commonly found on particulate matter (PM) and have been associated with the development of asthma and asthma exacerbation in urban populations. We examined time spent in the home and outdoors as predictors of exposures to airborne PAHs and measured urinary 1-hydroxypyrene-glucuronide (1-OHPG) as internal dose of PAHs in 118 children aged 5-12 years from Baltimore, MD. During weeklong periods (Saturday-Saturday) in each of four seasons: daily activities were assessed using questionnaires, indoor air nicotine and PM concentrations were monitored, and urine specimens were collected on Tuesday (day 3) and Saturday (day 7) for measurement of 1-OHPG. Time spent in non-smoking homes was associated with significantly decreased 1-OHPG concentration in urine (β=-0.045, 95% CI (-0.076, -0.013)), and secondhand smoke (SHS) exposures modified these associations, with higher urinary 1-OHPG concentrations in children spending time in smoking homes than non-smoking homes (P-value for interaction=0.012). Time spent outdoors was associated with increased urinary 1-OHPG concentrations (β=0.097, 95% CI (0.037, 0.157)) in boys only. Our results suggest that SHS and ambient (outdoor) air pollution contribute to internal dose of PAHs in inner city children.

Population-based comparison of biomarker concentrations for chemicals of concern among Latino-American and non-Hispanic white children

Differences in cultural and economic status may place ethnic subgroups of children at higher risk for exposure, leading to heightened health risks, and health inequities. Although Latino-Americans represent 22% of all children in the United States, few studies have explored within-group differences in their exposure to toxicants. Using socio-demographic and biomarker data from the National Health and Nutrition Examination Survey from 1999 to 2008, we characterized determinants of health and estimated geometric means of environmental contaminant biomarkers (blood concentrations of lead and mercury, serum concentrations of dichlorodiphenyldichloroethylene [p,p'-DDE] and cotinine, and urinary metabolites of organophosphate [OP] pesticides and polycyclic aromatic hydrocarbons [PAHs]) among 4,257 Mexican American (MA), 677 Other Latino-American (OL), and 3,370 Non-Hispanic White (NHW) children. MAs had the lowest levels of health insurance coverage and regular access to health care, and largest household size compared to NHWs and OLs. MAs had higher levels of p,p'-DDE, lead, and cadmium while OLs had higher estimates of mercury relative to other groups. MAs had higher urinary metabolite concentrations of 2-hydroxynaphthalene; otherwise MAs and OLs had lower concentrations of PAHs. NHWs had higher levels of cotinine and dimethylthiophosphate. For other OP metabolites, differences among groups were less clear. Lead and p,p'-DDE exposure differences likely reflect later and less regulatory control of these chemicals in Latin America. Additionally, poor quality housing with lead paint is more common in economically disadvantaged subpopulations. Dietary habits are possible sources of differential cadmium, mercury, and organophosphate exposure. Cotinine exposure differences by income and U.S.- vs. foreign-born may represent increased acculturation. These results, coupled with additional research on exposure sources may contribute to refinement of environmental health promotion programs for the fast-growing Latino-American population.

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.

Polycyclic aromatic hydrocarbons exposure and lung function decline among coke-oven workers: A four-year follow-up study

OBJECTIVES

This study aimed to investigate quantitative relationships of urinary PAH metabolites with lung function declines among coke-oven workers.

METHODS

We performed a prospective investigation involving 1243 workers with follow-up periods from 2010 to 2014. Their lung function measurements, including forced vital capacity (FVC), forced expiratory volume in one second (FEV1), the percentage of predicted FVC (FVC%) and FEV1 (FEV1%), FEV1/FVC ratio, and forced expiratory flow between 25% and 75% of vital capacity (FEF25-75), were detected in both baseline (2010) and follow-up study (2014). We also detected the urinary concentrations of 12 PAH metabolites in the baseline study. The relationships between the baseline urinary PAH metabolites and 4-year lung function declines were analyzed by multivariate linear regressions, with adjustment for potential confounders.

RESULTS

We found that the baseline concentrations of urinary 1-hydroxynaphthalene (1-OHNa), 2-OHNa, 2-hydroxyfluorene (2-OHFlu), 9-OHFlu, 1-hydroxyphenanthrene (1-OHPh), 2-OHPh, and ΣOH-PAHs were significantly associated with accelerated decline in FEV1/FVC [all β>0 and false discovery rate (FDR) P<0.05]. Additionally, the baseline levels of urinary 1-OHNa, 1-OHPh, 2-OHPh, 9-OHPh, 1-hydroxypyrene (1-OHP), and ΣOH-PAHs were associated with significantly deeper decline in FEF25-75 (all β>0 and FDR P<0.10). When using backward selection to adjustment for 10 urinary PAH metabolites, the most significant determiner for FEV1/FVC decline was 1-OHNa among nonsmokers and 9-OHFlu among smokers, and the significant determiner for FEF25-75 decline was 9-OHPh among nonsmokers and 1-OHP among smokers.

CONCLUSIONS

This longitudinal study revealed that higher baseline exposure levels of PAHs could lead to greater decline in lung function over a 4-year follow-up.

Polycyclic Aromatic Hydrocarbons: Part II, Urine Markers

There has been increasing demand for simple, rapid, highly sensitive, inexpensive yet reliable method for detecting predisposition to cancer. Human biomonitoring of exposure to the largest class of chemical carcinogen, polycyclic aromatic hydrocarbons (PAHs) that are rapidly transformed into detectable metabolites (eg, 1-hydroxypyrene), can serve as strong pointers to early detection of predisposition to cancer. Given that any exposure to PAH is assumed to pose a certain risk of cancer, several biomarkers have been employed in biomonitoring these ninth most threatening ranked compounds. They include metabolites in urine, urinary thioethers, urinary mutagenicity, genetoxic end points in lymphocytes, hemoglobin adducts of benzo(a)pyrene, PAH-protein adducts, and PAH-DNA adducts among others. In this chapter, the main focus will be on the urine metabolites since urine samples are easily collected and there is a robust analytical instrument for the determination of their metabolites.

Urinary monohydroxylated metabolites of polycyclic aromatic hydrocarbons in children living in city and rural residences in Southern China

Urinary 2-hydroxynaphthalene, 2-hydoxyfluorene, 9-hydroxyphenanthrene, 1-hydroxypyrene and 3-hydroxybenz[a]pyrene concentrations in 179 randomly selected voluntary students were determined in the Southern China, aged 14-16 and living in four areas with different levels of polycyclic aromatic hydrocarbons (PAHs) in soil, water and ambient air. The excretion of 1-hydroxypyrene is significantly higher in students of the urban than in students of the rural, while there are no significant differences of urinary 2-hydroxynaphthalene, 2-hydoxyfluorene and 9-hydroxyphenanthrene between urban and rural children. Mean concentrations of 1-hydroxypyrene (0.54-0.80 μmol/mol creatinine) in the study are much higher than those in the children of Denmark, Germany, Spain, USA, Korea, Japan and Taiwan, and a little higher than those in the children of Ukraine and Thailand. Urinary 2-hydroxynaphthalene concentrations in the study are a little higher than those in the children of USA, and similar to that in non-occupational exposure residences in Korea. Urinary 9-hydroxyphenanthrene concentrations in China are much higher than those in the children of USA. Differences between children with smoking parents and non-smoking parents are not significant in the study.

Exposure to low dose benzo[a]pyrene during early life stages causes symptoms similar to cardiac hypertrophy in adult zebrafish

Growing evidence indicates that polycyclic aromatic hydrocarbons (PAHs) can lead to cardiac hypertrophy and recent research indicates that exposure to low dose crude oil during early embryonic development may lead to impacts on heart health at later life stages. The aim of this study was to evaluate whether exposure during early life stages to low dose benzo[a]pyrene (BaP), as a high-ring PAH, would lead to cardiac hypertrophy at later life stages. Zebrafish were exposed to low dose BaP until 96 hpf, then transferred to clean water and maintained for a year before histological and molecular biological analysis. Our results showed that exposure to low level BaP during early life stages increased heart weight to body weight ratios and deposited collagen in the heart of adult zebrafish. ANP, BNP and c-Myc were also induced in the heart of adult zebrafish by BaP. These results proved that low level BaP exposure during early life stages caused symptoms similar to cardiac hypertrophy in adult zebrafish. Our results displayed an elevated expression of CdC42, RhoA, p-ERK1, 2 and Rac1. Therefore, the mechanism of the cardiac hypertrophy caused by BaP exposure during early life stages may be through inducing the expression of CdC42, RhoA and Rac1, together with activating ERK1, 2.

Concentrations and profiles of urinary polycyclic aromatic hydrocarbon metabolites (OH-PAHs) in several Asian countries

Concentrations of 12 hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) were determined in 306 urine samples collected from seven Asian countries (China, India, Japan, Korea, Kuwait, Malaysia, and Vietnam) by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The total concentrations of OH-PAHs found in the seven Asian countries were in the following increasing order: Malaysia (median: 2260 pg/mL) < Japan (4030 pg/mL) < China (5770 pg/mL) < India (6750 pg/mL) < Vietnam (8560 pg/mL) < Korea (9340 pg/mL) < Kuwait (10170 pg/mL). The measured urinary concentrations of 1-hydroxypyrene (1-PYR) in samples from Malaysia, Korea, and Japan (∼ 100 pg/mL) were similar to those reported for North America and Western Europe. The concentrations of 1-PYR in urine samples from China, India, and Vietnam were 4-10 times higher than those reported for other countries, thus far. Among the 12 OH-PAH compounds analyzed, hydroxynaphthalene (NAP: sum of 1-hydroxynaphthalene and 2-hydroxynaphthalene) was the dominant compound (accounting for 60-90% of total OH-PAHs), followed by hydroxyphenanthrene (PHEN: sum of 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, 4-hydroxyphenanthrene, and 9-hydroxyphenanthrene [3-16%]), 2-hydroxyfluorene (3-20%), and 1-PYR (2-8%). The total daily intakes (DIs) of PAHs were estimated based on the urinary concentrations of their metabolites. The DIs of naphthalene were found to be higher for populations in Korea, Kuwait, and Vietnam (> 10 μg/day) than those of the other countries studied (∼ 5 μg/day). The DIs of phenanthrene and pyrene (> 10 μg/day) in the populations of China, India, and Vietnam were higher than those estimated for the populations in the other countries studied (∼ 5 μg/day).

Polycyclic aromatic hydrocarbon exposure and pediatric asthma in children: a case-control study

BACKGROUND

Bronchial asthma is one of the most prevalent diseases in Arab children. Environmental pollution has been suggested to be considered causative of asthma, nasal symptoms and bronchitis in both children and adult. The objectives of this study were to evaluate the association between serum polycyclic aromatic hydrocarbons (PAHs) levels, asthma and allergic outcomes among Saudi children aged up to 15 yrs. We hypothesized that increased serum PAHs are associated with allergy, asthma, or respiratory symptoms.

METHODS

A total of 195 Saudi children (98 asthma pediatric patients and 97 healthy controls) were randomly selected from the Riyadh Cohort Study for inclusion. The diagnosis of Asthma was based on established pediatric diagnosis and medications taken.

RESULTS

Asthma related markers showed highly significant differences between children with and without asthma. Thus IgE, resistin and IL-4 were significantly increased (p 0.004, 0.001 and 0.003, respectively) in children with asthma compared with non-asthma control subjects. GMCSF, IFN-γ, IL-5, IL-8 and IL-10, on the other hand, were significantly decreased in children with asthma (p 0.003, 0.03, 0.001, 0.004 and 0.03, respectively). Strong associations between serum PAHs levels and biomarkers of childhood asthma were detected in Arabic children. Data confirmed the role of naphthalene, 4H-cyclobenta[def]phenanthrene, 1,2-benzanthracene, chrysene and benzo(e)acephenanthrylene in childhood asthma; levels of these PAHs were correlated with asthma related biomarkers including IgE, resistin, GMCSF and IFN-γ as well as IL-4, IL-5, IL-8 and IL-10 cytokines.

CONCLUSIONS

This data highlight the pivotal role of specific PAHs in childhood asthma.

Preliminary study of children's exposure to PAHs and its association with 8-hydroxy-2'-deoxyguanosine in Guangzhou, China

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous air pollutants generated mainly from incomplete combustion such as automobile exhaust and cigarette smoke. Oxidative stress is believed to be involved in carcinogenesis, and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was used as the biomarker to assess such DNA damage. The children's urinary PAH metabolite (OH-PAHs) level were explored in Guangzhou and their associations with 8-OHdG. Two groups of subjects were selected: (1) one group (n=39, 6-7 years old) from an elementary school situated near a heavy traffic road (polluted area) and (2) another group (n=35, 4-6 years old) from a kindergarten situated in a corner of the main campus of a big university (non-polluted area). Urinary 8-OHdG and nine urinary monohydroxylated PAH metabolites were measured, including 2-hydroxynaphthalene (2-OHN), 2-hydroxyfluorene (2-OHF), 2-, 3-, 4-, 9-hydroxyphenanthrene (2-, 3-, 4-, 9-OHPhe), 1-hydroxypyrene (1-OHP), 6-hydroxychrysene (6-OHChr) and 3-hydroxybenzo(a)pyrene (3-OHBaP). All other PAH metabolites were detected in urine samples from both children groups except for 6-OHChr and 3-OHBaP. Levels of 2-OHN, 2-OHF, 3-OHPhe, 9-OHPhe and 1-OHP were significantly different between two groups (P<0.05, T-test). The elementary school children from the polluted area had higher urinary levels of 2-OHN, 2-OHF, 2-, 3-, 4-OHPhe and 1-OHP ((9.10±7.39, 3.72±2.91, 0.32±0.50, 0.37±0.28, 0.23±0.29 and 0.64±0.07 μmol/mol creatinine, respectively) than those from the control group. The results suggested that heavy traffic pollution led to higher PAH body burden. There existed no significant difference for urinary 8-OHdG concentration between two groups (p>0.05, T-test), and no strong correlations between the individual OH-PAHs and 8-OHdG. However, the urinary 8-OHdG concentration in the elementary school children from the traffic polluted area was slightly higher than those in the non-polluted area (20.87±14.42 μmol/mol creatinine vs. 16.78±13.30 μmol/mol creatinine). It may be that the potential co-exposure of the children to other pollutants affects 8-OHdG concentration besides the PAHs.

Urinary metabolites before and after cleanup and subjective symptoms in volunteer participants in cleanup of the Hebei Spirit oil spill

BACKGROUND

On December 7th, 2007, the Hong Kong tanker Hebei Spirit (HS) (146,848 tons) was crushed by a crane ship near the shore of Taean, Korea. More than 12,547 kl of crude oil spilled into the sea and contaminated the western coastline of the Korean peninsula. For a period of six months after the accident, approximately 1,000,000 volunteers participated in the cleanup. Our goal in this study was to examine the exposure status and acute health effects on volunteers that participated in the oil spill cleanup.

METHODS

A survey questionnaire was filled out by 565 volunteers, requesting information regarding physical symptoms. Out of the total number of participants, urine samples from 105 university student volunteers were collected before and after the cleanup work, and metabolite levels of volatile organic compounds and polycyclic aromatic hydrocarbons were analyzed.

RESULTS

Volunteers that participated for longer cleanup work reported an increase in physical symptoms including visual disturbance, nasal and bronchus irritation, headaches, heart palpitations, fatigue and fever, memory and cognitive disturbance, and abdominal pain. The levels of t,t-muconic acid, mandelic acid, and 1-hydroxypyrene were significantly higher in samples after cleanup than those measured before participation (p<0.05). Other than the associated risk of dermal irritation with the difference in the t,t-muconic acid level between the post- to pre-cleanup levels, no other physical symptoms demonstrated a significant association with changes observed in the levels of urinary metabolites.

CONCLUSIONS

Based on the significant increase of subjective symptoms in volunteers participating in the study, monitoring of the long term health effects, focusing on those with longer exposure, is warranted.

Polycyclic aromatic hydrocarbon (1-OHPG and 2-naphthol) and oxidative stress (malondialdehyde) biomarkers in urine among Korean adults and children

Using the urinary biomarkers 1-hydroxypyrene-glucuronide (1-OHPG), 2-naphthol, and malondialdehyde (MDA), we evaluated seasonal and regional variations in polycyclic aromatic hydrocarbon (PAH) exposure and oxidative stress among Korean adults and children. In total, 322 children (175 male and 147 female) and 332 adults (47 male and 285 female) were recruited in two regions of Korea, one representing a metropolitan area (Seoul/Incheon) and the other an industrial (Pohang) area, from winter 2002 to spring 2003. The subjects voluntarily gathered their first morning urine void, which was immediately transported to our laboratory and stored at -20 °C. Urinary 1-OHPG was measured by synchronous fluorescence spectroscopy, 2-naphthol by HPLC, and urinary MDA by HPLC with a UV detector. The median urinary 1-OHPG concentration tended to be higher in the industrial region than in the metropolitan region (0.92 vs. 0.77 ng/mL; p=0.03), and higher in winter than in spring (0.95 vs. 0.73 ng/mL; p<0.001). The median 2-naphthol concentration was also higher in the industrial region than in the metropolitan region (21.0 vs. 12.3 ng/mL; p<0.0001), but was higher in spring than in winter (19.7 vs. 10.3 ng/mL; p<0.0001). The median MDA concentration was significantly higher in winter than in spring (2.19 vs. 1.03 μmol/L; p<0.0001), whereas regional variation in MDA was observed only in female adults (p=0.02). In winter, the level of 1-OHPG was higher in children exposed to environmental tobacco smoke than in unexposed children (0.94 vs. 0.86 ng/mL; p=0.02). Our results indicate that both region and season can significantly influence the levels of PAH exposure and oxidative stress biomarkers.

Assessment of non-occupational exposure to polycyclic aromatic hydrocarbons through personal air sampling and urinary biomonitoring

Non-occupational inhalation and ingestion exposure to polycyclic aromatic hydrocarbons (PAHs) has been studied in 8 non-smoking volunteers through personal air sampling and urinary biomonitoring. The study period was divided into 4 segments (2 days/segment), including weekdays with regular commute and weekends with limited traffic related exposures; each segment had a high or low PAH diet. Personal air samples were collected continuously from the subjects while at home, at work, and while commuting to and from work. All urine excretions were collected as individual samples during the study. In personal air samples, 28 PAHs were measured, and in urine samples 9 mono-hydroxylated metabolites (OH-PAHs) from 4 parent PAHs (naphthalene, fluorene, phenanthrene and pyrene) were measured. Naphthalene was found at higher concentrations in air samples collected at the subjects' residences, whereas PAHs with four or more aromatic rings were found at higher levels in samples taken while commuting. Urinary OH-PAH biomarker levels increased following reported high inhalation and/or dietary exposure. On days with a low PAH diet, the total amount of inhaled naphthalene during each 24-hour period was well correlated with the amount of excreted naphthols, as was, to a lesser extent, fluorene with its urinary metabolites. During days with a high dietary intake, only naphthalene was significantly correlated with its excreted metabolite. These findings suggest that this group of non-occupational subjects were exposed to naphthalene primarily through indoor air inhalation, and exposed to other PAHs such as pyrene mainly through ingestion.

Polycyclic aromatic hydrocarbon metabolite levels and pediatric allergy and asthma in an inner-city cohort

Exposure to polycyclic aromatic hydrocarbons (PAH) has been associated with allergic sensitization and asthma. We hypothesized that increased urinary PAH metabolites are associated with allergy or asthma among children age 5 yrs in an inner-city birth cohort. As part of an ongoing prospective birth cohort under the auspices of the Columbia Center for Children's Environmental Health (CCCEH), urine was collected from 5-yr-old children (n = 222) of Dominican American and African American mothers in Northern Manhattan and South Bronx of New York City. Twenty-four PAH metabolites were measured in these specimens, and their levels (unadjusted and specific gravity corrected) were evaluated with IgE levels and asthma outcomes. Ten metabolites were detected in urine from all children. Concentrations ranged higher than those in representative samples of US children ages 6-11 in the National Health and Nutrition Examination Survey (NHANES). Among CCCEH children, compared with African Americans, the Dominican children had higher 2-hydroxynaphthalene but lower 9-hydroxyfluorene and 4-hydroxyphenanthrene concentrations. Increased 3-hydroxyfluorene and 3-hydroxyphenanthrene levels were associated with higher anti-mouse IgE levels (p < 0.05). These plus 2-hydroxynaphthalene, 2-hydroxyflourene and 1-hydroxyphenanthrene concentrations were associated with higher anti-mouse IgE levels on multivariate analyzes. Increased 2-hydroxyphenanthrene, 3-hydroxyphenanthrene and 4-hydroxyphenanthrene levels were associated with higher anti-cat IgE levels (p < 0.05) in univariate, but not multivariate, analyzes. Levels of PAH metabolites were not associated with respiratory symptoms. Measures of PAH metabolites suggest considerable exposure in an urban pediatric population, and possible associations with allergic sensitization to mouse.

Seasonal and regional contributors of 1-hydroxypyrene among children near a steel mill

Urinary 1-hydroxypyrene (1-OHP) is a biomarker of exposure to polycyclic aromatic hydrocarbons (PAH). Effect of residence on children's PAH exposure was reported among children living near a polluted area. Instead of a snapshot assessment, however, a temporal history of exposure characteristics needs to be assessed in the studies of chronic disease development such as cancer. The urinary 1-OHP measurements were repeated to determine regional effect of ambient air pollution on 1-OHP levels over extended periods. Two sites were chosen: (a) one site located near the steel mill ("nearby" site) and (b) the other site located at a longer distance from the mill ("remote" site). Spot urinary 1-OHP levels were measured from 72 children for 3 consecutive days per month, repeated over 9-month period. Compared with remote site, the nearby site had increased the urinary 1-OHP level by 62.3% [95% confidence interval (95% CI), 39.8-88.3%]. Other statistically significant factors that contributed to the level include sex [16.5% (95% CI, 1.2-34.1%) higher for girls than boys], consumption of charbroiled meat [16.5% (95% CI, 1.1-34.2%) higher], and an increase in PM(10) [10.1% (95% CI, 4.8-15.7%) higher for the interquartile range increment]. Controlling for covariates, the 1-OHP levels were increased in the summer and fall compared with winter. The magnitude of the effects of both seasons had diminished after adjusting for PM(10). This is the first report providing seasonal and regional contributors to environmental PAH exposure, assessed by urinary 1-OHP, with higher 1-OHP levels during summer when ambient pollution was also high.

Stability and intra-individual variation of urinary malondialdehyde and 2-naphthol

OBJECTIVES

Malondialdehyde (MDA), a lipid peroxidation by-product, has been widely used as an indicator of oxidative stress. Urinary 2-naphthol, a urinary PAH metabolite, is used as a marker of ambient particulate exposure and is associated with lung cancer and chronic obstructive pulmonary disease. However, the stability and intra-individual variation associated with urinary MDA and 2-naphthol have not been thoroughly addressed. The objective of this study was to assess the stability and intraindividual variation associated with urinary MDA and 2-naphthol.

METHODS

Urine samples were collected from 10 healthy volunteers (mean age 34, range 27 approximately 42 years old). Each sample was divided into three aliquots and stored under three different conditions. The levels of urinary MDA and 2-naphthol were analyzed 1) just after sampling, 2) after storage at room temperature (21 degrees C) for 16 hours, and 3) after storage in a -20 degrees C freezer for 16 hours. In addition, an epidemiological study was conducted in 44 Chinese subjects over a period of 3 weeks. The urinary MDA and 2-naphthol were measured by HPLC three times.

RESULTS

There was no difference in the levels of urinary MDA and 2-naphthol between the triplicate measurements (n=10, p=0.84 and p=0.83, respectively). The intra-class correlation coefficients (ICC) for urinary MDA and 2-naphthol were 0.74 and 0.42, respectively. However, the levels of PM2.5 in the air were well correlated with the levels of both MDA and 2-naphthol in the epidemiological study.

CONCLUSIONS

These results suggest that urinary MDA and 2-naphthol remain stable under variable storage conditions, even at room temperature for 16 hours, and indicate that these markers can be used in epidemiological studies involving various sample storage conditions. The intra-CC of urinary 2-naphthol and MDA were acceptable for application to epidemiological studies.

Concentration and profile of 22 urinary polycyclic aromatic hydrocarbon metabolites in the US population

Urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) are a class of PAH metabolites used as biomarkers for assessing human exposure to PAHs. The Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey (NHANES) uses OH-PAHs to establish reference range concentrations for the US population, and to set benchmarks for future epidemiologic and biomonitoring studies. For the years 2001 and 2002, 22 OH-PAH metabolites were measured in urine specimens from 2748 NHANES participants. Percentages of samples with detectable levels ranged from nearly 100% for metabolites of naphthalene, fluorene, phenanthrene, and pyrene, to less than 5% for metabolites from parent compounds with higher molecular weight such as chrysene, benzo[c]phenanthrene, and benz[a]anthracene. The geometric mean for 1-hydroxypyrene (1-PYR)--the most commonly used biomarker for PAH exposure--was 49.6 ng/L urine, or 46.4 ng/g creatinine. Children (ages 6-11) generally had higher levels than did adolescents (ages 12-19) or adults (ages 20 and older). Model-adjusted, least-square geometric means for 1-PYR were 87, 53 and 43 ng/L for children, adolescents (ages 12-19) and adults (ages 20 years and older), respectively. Log-transformed concentrations for major detectable OH-PAHs were significantly correlated with each other. The correlation coefficients between 1-PYR and other metabolites ranging from 0.17 to 0.63 support the use of 1-PYR as a useful surrogate representing PAH exposure.

1-Hydroxypyrene as a biomarker of PAH exposure among subjects living in two separate regions from a steel mill

OBJECTIVE

Steel mills are known to be a source of ambient polycyclic aromatic hydrocarbons (PAHs), and increased cancer risk has been reported among neighborhoods previously. In this study, we tried to assess the exposure to PAHs among residents nearby to a large steel mill in Korea by measuring urinary 1-hydroxypyrene (1-OHP).

METHODS

Two separate areas at different distances from a steel mill but on the same wind direction were chosen to evaluate the environmental exposures to polycyclic aromatic hydrocarbons. Three-hundred and fifty children living in the vicinity of steel plant ("nearby" group) and 606 children residing much farther from the factory ("remote" group) participated. Urine was collected on three consecutive days, and questionnaires about exposure to passive smoking and food consumption as well as demographics were obtained. Routine monitoring data of ambient pollutants were obtained and particulate matter less than 10 microm (PM10) was analyzed with multiple regressions to assess the associations with urinary 1-OHP.

RESULTS

The geometric mean concentration of urinary 1-OHP among nearby group (0.048+/-1.878 micromol/mol creatinine, GM+/-GSD) was approximately 1.3 times higher than that among remote group (0.036+/-2.425 micromol/mol creatinine, GM+/-GSD), and using multiple regression techniques, the difference was significant (P<0.0001) after adjusting for confounding variables. When different periods before the sampling of urine were examined, PM10 averages over 2 days, 3 days, and 1 week prior to urine sampling showed significant associations with urinary 1-OHP levels.

CONCLUSION

Our findings are consistent with the interpretation that residents nearby to a steel mill are exposed to PAHs through ambient exposures.

Estimating exposure to polycyclic aromatic hydrocarbons: a comparison of survey, biological monitoring, and geographic information system-based methods

Our objective was to compare polycyclic aromatic hydrocarbon (PAH) exposure estimates based on survey, biological monitoring, and geographic information system (GIS) methods. The 304 participants in this study supplied a urine sample and completed questionnaires about exposure to potential PAH sources. We assayed urine samples for 1-hydroxypyrene-O-glucuronide (1-OHPG), the major metabolite of pyrene, a common PAH. We used a GIS to estimate traffic exhaust exposure using vehicle count data at the residence and workplace. The five subjects who reported smoking during the 48-hour period had median 1-OHPG concentrations 10-fold that of nonsmokers (1.6 versus 0.16 pmol/mL; P = 0.01). Among nonsmokers, those who reported eating grilled, roasted, or broiled meat had significantly higher 1-OHPG concentrations than those who did not reported eating meat prepared by these methods (0.25 versus 0.06 pmol/mL; P = 0.02). Nonsmokers who reported traveling on roads for > or =3 hours during the 48-hour period also had significantly higher 1-OHPG levels than those who traveled <3 hours (0.23 versus 0.11 pmol/mL; P = 0.03). 1-OHPG levels were also correlated with hours of secondhand smoke exposure among nonsmokers (P = 0.04). In this study, 1-OHPG urine concentrations were not associated with self-reported exposures to cooking smoke, wood burning, or traffic levels near the home or to traffic density or urban/rural status determined using a GIS. Self-reported indicators of residential proximity to high traffic volume were, however, associated with GIS traffic density measures.

Design issues in cross-sectional biomarkers studies: urinary biomarkers of PAH exposure and oxidative stress

Cross-sectional biomarker studies can provide a snapshot of the frequency and characteristics of exposure/disease in a population at a particular point in time and, as a result, valuable insights for delineating the multi-step association between exposure and disease occurrence. Three major issues should be considered when designing biomarker studies: selection of appropriate biomarkers, the assay (laboratory validity), and the population validity of the selected biomarkers. Factors related to biomarker selection include biological relevance, specificity, sensitivity, biological half-life, stability, and so on. The assay attributes include limit of detection, reproducibility/reliability, inter-laboratory variation, specificity, time, and cost. Factors related to the population validity include the frequency or prevalence of markers, greater inter-individual variation than intra-individual variation, intra-class correlation coefficients (ICC), association with potential confounders, invasiveness of specimen collection, and subject selection. Three studies are selected to demonstrate different features of cross-sectional biomarker studies: (1) characterizing the determinants of the biomarkers (study I: urinary PAH metabolites and environmental particulate exposure), (2) relationship of multiple biomarkers of exposure and effect (study II: relationship between urinary PAH metabolites and oxidative stress), and (3) evaluating gene-environmental interaction (study III: effect of genetic polymorphisms of GSTM1 on the association of green tea consumption and urinary 1-OHPG levels in shipbuilding workers).