Determination of 1-hydroxypyrene in children urine using column-switching liquid chromatography and fluorescence detection

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.

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.

A gold nanoparticle-based colorimetric probe for rapid detection of 1-hydroxypyrene in urine

Direct and rapid detection of 1-hydroxypyrene (1-OHP) is of great importance owing to its high carcinogenicity, teratogenicity and toxicity.

Assessment of the levels of urinary 1-hydroxypyrene and air polycyclic aromatic hydrocarbon in PM2.5 for adult exposure to the petrochemical complex emissions

The relationship between external exposure and internal doses of polycyclic aromatic hydrocarbons (PAHs) has not been established for people living in industrial areas. This study was carried out to estimate the relationship between particle-phase PAH exposure and urinary 1-hydroxypyrene (1-OHP) levels among the adults living near a large petrochemical complex in Mailiao, Taiwan. We measured urinary 1-OHP in 781 residents above 35 years old and PM2.5 PAHs within a 20-km radius downwind from the petrochemical complex. Urinary 1-OHP was analyzed by high performance liquid chromatography, while 16 ambient particle-phase PAHs were measured by gas chromatography mass spectrometry. External exposures to individual PAHs at each study subject's address were estimated by kriging interpolation from air sampling results and regressed against the subjects' urinary 1-OHP levels, adjusting for confounding factors. The study population's urinary 1-OHP levels ranged from 0.001 to 3.005 μmol/mol-creatinine with significantly higher levels for females, grilled food consumers, and residents living close to roads. All 16 particle-phase PAHs were present in the study area with total PAH concentrations ranging from 0.111 to 1.982 ng/m(3). The spatial distribution of 4- and 5-ring PAHs identified high-concentration hotspots close to the complex in Mailiao. The multiple regression models showed that the adults' urinary 1-OHP levels were significantly correlated with 5 out of the 16 PAHs, including benzo[a]anthracene, benzo[k]fluoranthene, fluoranthene, pyrene, and dibenzo[a,h]anthracene; a 0.01 ng/m(3) increase in the concentration of these 5 PAHs at the study subjects' addresses was associated with a 20% elevation in urinary 1-OHP levels (μg/g-creatinine). Emissions from a petrochemical complex can elevate particle-phase PAH concentrations in surrounding areas and increase the urinary 1-OHP levels of adults living nearby.

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.

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).

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 levels of 1-hydroxypyrene in children residing near a coal-fired power plant

BACKGROUND

The effects of emissions from coal-fired power plants on children's exposure to polycyclic aromatic hydrocarbons (PAHs) are not well understood.

OBJECTIVES

This study aimed to evaluate the sources and the urinary levels of 1-hydroxypyrene, a biomarker of exposure to PAHs, among children living in proximity to a coal-fired power plant.

METHODS

Study areas consisted of two high exposure and two low exposure communities, at different distances and directions from a large coal-fired power plant in central Taiwan. Study subjects included 369 children aged 1-13 years and randomly selected from each community. Each child's urinary 1-hydroxypyrene concentration was measured by a high-performance liquid chromatography-fluorescence detector method. Samples of ambient air were analyzed for PAHs using a gas chromatography-mass spectrometry method. Information on important factors was collected by an interview using a structured questionnaire. Multiple regression analysis was used to assess factors significantly associated with urinary 1-hydroxypyrene levels.

RESULTS

Levels of PAHs in ambient air in the high exposure communities were higher than those in the low exposure communities. Children living in high exposure communities had higher mean urinary 1-hydroxypyrene concentrations than those in low exposure communities (0.186 and 0.194 vs. 0.113 and 0.122 μmol/mol-creatinine, respectively). The difference in urinary 1-hydroxypyrene levels between the high exposure communities and one low exposure community remained significant after adjusting for age, gender, environmental tobacco smoke, dietary exposure, and traffic.

CONCLUSIONS

Children living in communities downwind of and in proximity to the coal-fired power plant had significantly increased urinary 1-hydroxypyrene levels.

Resonance Light Scattering of 1-Hydroxypyrene-Ethyl Violet-Anionic Surfactant System and Its Analytical Application

A novel method for the rapid and sensitive analysis of 1-hydroxypyrene (1-OHP) in human urine has been developed that uses a resonance light scattering (RLS) technique. The assay was based on the interaction of ethyl violet (EV) with 1-hydroxypyrene to form an ion-associate complex, which resulted in the enhancement of RLS intensity and the appearance of new RLS spectra. In the presence of anionic surfactant, the maximum RLS peak of the system was located at 396 nm at pH 8.0. Under the optimum conditions, it was found that the enhanced RLS intensity was directly proportional to the concentration of 1-hydroxypyrene in the range of 4.0 - 982 microg l(-1). The detection limit was 1.2 microg l(-1) and the recoveries of 1-hydroxypyrene were 92.8 - 102.3% (n = 6). The proposed method was successfully applied to the analysis of human urine samples. The results of 1-hydroxypyrene were in agreement with those obtained by the method of high-performance liquid chromatography.

Automated on-line liquid chromatography–photodiode array–mass spectrometry method with dilution line for the determination of bisphenol A and 4-octylphenol in serum

A novel on-line liquid chromatography-photodiode array detection-mass spectrometry (LC-DAD-MS) system was established with restricted-access media (RAM) pre-column and dilution line combined with a column-switching valve. The serum samples were injected directly onto pre-column under diluted condition by dilution line. After elution of proteins in the serum, the analytes were backflushed onto an ODS analytical column using a six-port column-switching device. The influence of the composition of the mobile phase, for instance, organic modifer, ionic strength, pH, dilution times and the rotation time of the switching valve have been investigated using bisphenol A (BPA) and 4-octyphenol (4-OP) as analytes. The evaluations for peak responses and sensitivity were conducted by MS, and proteins were removed by RAM-column with DAD monitoring at 280 nm. The peak shape was improved by adding a dilution line, especially in the case of large volume injection (LVI), which increased the sensitivity of the analysis. The selective and sensitive quantification of BPA and 4-OP in serum sample could be finished within 25 min. The method had linearity in the range 0.1-500 ng/mL with a limit of quantification for BPA and 4-OP of 0.1 and 0.5 ng/mL, respectively. The recoveries were in the range of 80-101% with less than 9.0% RSDs. This on-line LC-MS method demonstrates potential application to evaluating the exposure and risk of BPA and 4-OP in human.