Stability issues in the determination of 19 urinary (free and conjugated) monohydroxy polycyclic aromatic hydrocarbons

Renal excretion of 1,2-dihydroxynaphthalene (DHN) in firefighting instructors after exposure to polycyclic aromatic hydrocarbons (PAHs) during live fire training

Exposure of firefighting instructors to polycyclic aromatic hydrocarbons (PAHs) such as naphthalene is unavoidable during live fire training. The study aimed to investigate naphthalene uptake by measuring the urinary excretion of the naphthalene metabolite 1,2-dihydroxynaphthalene (DHN), to describe the DHN elimination kinetics and to evaluate the results by comparison to further biomarkers of PAH exposure. N = 6 male non-smoking firefighting instructors completed five training sessions each in a residential fire simulation unit under respiratory protection. All participants provided two urine samples before and another seven samples within an 18-h-interval after each session. DHN was detected by gas chromatography/tandem mass spectrometry (GC-MS/MS) in all samples (n = 237) with median concentrations ranging from 3.3 µg/g crea. (range 0.9-10.2) before exposure to 134.2 µg/g crea. (43.4-380.4) post exposure. Maximum elimination found 3.3 h (median) after onset of exposure decreased with a mean half-life of 6.6 h to 27.1 µg/g crea. (15.7-139.5) 18 h after training. DHN sensitively indicated a presumed dermal naphthalene intake during training, showing similar elimination kinetics like other naphthalene metabolites. Internal exposure of the participants transiently exceeded exposures determined for non-smokers in the general population, but was lower than at other workplaces with PAH exposure. Despite limited uptake, accumulation is possible with daily exposure.

Flexible filament winding strategy to prepare COF@polyionic liquid-coated fibers for non-selective exclusion of macromolecules in electro-enhanced solid-phase microextraction

BACKGROUND

Accurate quantitative analysis of small molecule metabolites in biological samples is of great significance. Hydroxypolycyclic aromatic hydrocarbons (OH-PAHs) are metabolic derivatives of emerging pollutants, reflecting exposure to polycyclic aromatic hydrocarbons (PAHs). Macromolecules such as proteins and enzymes in biological samples will interfere with the accurate quantification of OH-PAHs, making direct analysis impossible, requiring a series of complex treatments such as enzymatic hydrolysis. Therefore, the development of matrix-compatible fiber coatings that can exclude macromolecules is of great significance to improve the ability of solid-phase microextraction (SPME) technology to selectively quantify small molecules in complex matrices and achieve rapid and direct analysis.

RESULTS

We have developed an innovative coating with a stable macromolecular barrier using electrospinning and flexible filament winding (FW) technologies. This coating, referred to as the hollow fibrous covalent organic framework@polyionic liquid (F-COF@polyILs), demonstrates outstanding conductivity and stability. It accelerates the adsorption equilibrium time (25 min) for polar OH-PAHs through electrically enhanced solid-phase microextraction (EE-SPME) technology. Compared to the powder form, F-COF@polyILs coating displays effective non-selective large-size molecular sieving. Combining gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS), we have established a simple, efficient quantitative analysis method for OH-PAHs with a low detection limit (0.008-0.05 ng L-1), wide linear range (0.02-1000 ng L-1), and good repeatability (1.0%-7.3 %). Experimental results show that the coated fiber exhibits good resistance to matrix interference (2.5%-16.7 %) in complex biological matrices, and has been successfully used for OH-PAHs analysis in human urine and plasma.

SIGNIFICANCE

FW technology realizes the transformation of the traditional powder form of COF in SPME coating to a uniform non-powder coating, giving its ability to exclude large molecules in complex biological matrices. A method for quantitatively detecting OH-PAHs in real biological samples was also developed. Therefore, the filament winding preparation method for F-COF@polyILs coated fibers, along with fibrous COFs' morphology control, has substantial implications for efficiently extracting target compounds from complex matrices.

Biomonitoring of polycyclic aromatic hydrocarbons in firefighters at fire training facilities and in employees at respiratory protection and hose workshops

Introduction

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic to humans and are formed by incomplete combustion. PAHs are always present during firefighting operations, and fire department members can be exposed to them in the workplace.

Methods

In this study, we analyzed 1-hydroxypyrene (1-OHP) in 36 urine samples from nine firefighters, collected before and after fire training sessions, and 32 urine samples from eight employees at respiratory protection and hose workshops. To assess breakthrough PAH exposure through personal protective equipment and potential dermal uptake, some of the workshop employees wore cotton garments under their regular workwear. Cotton samples were then examined for the presence of 17 semi-volatile and low-volatility PAHs.

Results

After firefighting exercises, we observed approximately a fivefold increase in mean 1-OHP concentrations in samples from firefighters, from 0.24 μg/L to 1.17 μg/L (maximum: 5.31 μg/L). In contrast, 1-OHP levels in workshop employees were found to be low, with the majority of urine samples yielding concentrations below the limit of quantification (LOQ: 0.05 μg/L, maximum: 0.11 μg/L). Similarly, low PAH levels were found on the workshop employees' cotton undergarments, with maximum concentrations of 250 and 205 ng/g for pyrene and benzo[a]pyrene, respectively.

Discussion

In conclusion, significant increases in 1-OHP in urine were observed in firefighters after training sessions, whereas work-related exposure remained low among workshop employees.

Simultaneous extraction of hydroxylated polycyclic aromatic hydrocarbons and catecholamines with magnetic boronic acid hypercrosslinked polymers

Urinary hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and catecholamines (CAs) are important biomarkers of PAHs exposure. In this study, a novel magnetic boronic acid hypercrosslinked composite (Fe3O4@HCP-BA) is synthesized using a facile one-pot strategy and applied as a sorbent for the simultaneous extraction of OH-PAHs and CAs in urine samples. The synthesized Fe3O4@HCP-BA composites are characterized by rich pore structure, highly specific surface area, good magnetic response, and excellent selectivity and adsorption efficiency (range: 65.26-496.71 and 1227.3-1581.8 µmol g-1 for CAs and OH-PAHs, respectively). The mechanisms governing the adsorption of the OH-PAHs and CAs to the Fe3O4@HCP-BA composites were systematically studied via adsorption kinetics, isotherm models, XPS characterization, and molecular simulation. The resultant Fe3O4@HCP-BA composite-based MSPE/HPLC-FLD method exhibited good linearity (R2 > 0.9916), low limits of detection (0.2-0.3 pg mL-1 and 0.2-0.3 ng mL-1 for OH-PAHs and CAs, respectively), and good precision (intra-day and inter-day RSDs < 11.1%). The analysis of CAs and OH-PAHs in the urine samples from 14 smokers and 14 non-smokers revealed a positive correlation between the concentrations of CAs and OH-PAHs. Our findings not only establish the proposed method as a green, environmentally friendly, and simple strategy for preparing magnetic adsorbents, but also confirm it as a promising alternative method for accurate determination of OH-PAHs and CAs in biological samples.

New sensitive LC-MS/MS method for the simultaneous determination of 13 phenolic and carboxylic acid pesticide biomarkers in human urine, including dicamba

The commercialization in 2016 of genetically engineered seeds tolerant to dicamba and/or 2,4-dichlorophenoxyacetic acid (2,4-D) has caused a rapid increase in the use of these herbicides. New questions about the reproductive and chronic health effects of long-term exposure to these herbicides have been raised. To assess exposure to dicamba and other pesticides of interest in the Heartland Study, a birth cohort study based in the United States, a new analytical method was needed. The present study describes the development and validation of this new solid phase extraction and liquid chromatography-tandem mass spectrometry method that detects simultaneously 13 pesticides or their metabolites in 250 μL of urine. More specifically, the method allows the analysis of dicamba, 2,4-D and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), which are herbicides, of malathion dicarboxylic acid (MDA), para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TCPy), 2-diethylamino-6-methylpyrimidin-4-ol (DEAMPY) and 2-isopropyl-6-methyl-4-pyrimidinol (IMPY), which are metabolites of organophosphate insecticides, and finally of cis-3-(2,2-Dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA), trans-3-(2,2-Dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (trans-DCCA), 3-Phenoxybenzoic acid (3-PBA), 4-Fluoro-3-phenoxybenzoic acid (4-F-3-PBA) and cis-3-(2,2-Dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DBCA), which are metabolites of synthetic pyrethroids insecticides. The method was validated under ISO/IEC 17025 guidance. The limit of detection (LOD) in urine samples was 0.10 μg/L for dicamba, while the LOD for other analytes ranged between 0.0038 μg/L and 0.091 μg/L. Accuracy was evaluated by analyzing samples from two External Quality Assessment Schemes, namely G-EQUAS and OSEQAS. Preliminary results obtained following the analysis of 91 urine samples taken from pregnant women enrolled in the Heartland Study are presented here. This method is suitable for human biomonitoring studies.

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.

Miniaturized method for the quantification of persistent organic pollutants and their metabolites in HepG2 cells: assessment of their biotransformation

Biotransformation can greatly influence the accumulation and, subsequently, toxicity of substances in living beings. Although traditionally these studies to quantify metabolization of a compound have been carried out with in vivo species, currently, in vitro test methods with very different cell lines are being developed for their evaluation. However, this is still a very limited field due to multiple variables of a very diverse nature. So, an increasing number of analytical chemists are working with cells or other similar biological samples of very small size. This makes it necessary to address the development of analytical methods that allow determining their concentration both inside the cells and in their exposure medium. The aim of this study is to develop a set of analytical methodologies for the quantification of polycyclic aromatic hydrocarbons, PAHs (phenanthrene, PHE), and polybrominated diphenyl ethers, PBDEs (2,2',4,4'-tetrabromodiphenyl ether, BDE-47), and their major metabolites in cells and their exposure medium. Analytical methodologies, based on miniaturized ultrasound probe-assisted extraction, gas chromatography-mass spectrometry-microelectron capture detector (GC-MS-µECD), and liquid chromatography-fluorescence detector (LC-FL) determination techniques, have been optimized and then applied to a biotransformation study in HepG2 at 48 h of exposure. Significant concentrations of the major metabolites of PHE (1-OH, 2-OH, 3-OH, 4-OH-, and 9-OH-PHE) and BDE-47 (5-MeO-, 5-OH-, and 3-OH-BDE-47) were detected and quantified inside the cells and in the exposure medium. These results provide a new method for determination and improve information on the metabolization ratios for a better knowledge of the metabolic pathways and their toxicity.

External Quality Assurance Schemes (EQUASs) and Inter-laboratory Comparison Investigations (ICIs) for human biomonitoring of polycyclic aromatic hydrocarbon (PAH) biomarkers in urine as part of the quality assurance programme under HBM4EU

Polycyclic aromatic hydrocarbons (PAHs) were included as priority substances for human biomonitoring (HBM) in the European Human Biomonitoring Initiative (HBM4EU), which intended to harmonise and advance HBM across Europe. For this project, a specific Quality Assurance and Quality Control (QA/QC) programme applying Inter-laboratory Comparison Investigations (ICIs) and External Quality Assurance Schemes (EQUASs) was developed to ensure the comparability and accuracy of participating analytical laboratories. This paper presents the results of four ICI/EQUAS rounds for the determination of 13 PAH metabolites in urine, i.e. 1-naphthol, 2-naphthol, 1,2-dihydroxynaphthalene, 2-, 3- and 9-hydroxyfluorene, 1-, 2-, 3-, 4- and 9-hydroxyphenanthrene, 1-hydroxypyrene and 3-hydroxybenzo(a)pyrene. However, 4 PAH metabolites could not be evaluated as the analytical capacity of participating laboratories was too low. Across all rounds and biomarkers, 86% of the participants achieved satisfactory results, although low limits of quantification were required to quantify the urinary metabolites at exposure levels of the general population. Using high-performance liquid or gas chromatography coupled with mass spectrometry (HPLC-MS; GC-MS) and isotope dilution for calibration as well as performing an enzymatic deconjugation step proved to be favourable for the accurate determination of PAHs in urine. Finally, the HBM4EU QA/QC programme identified an international network of laboratories providing comparable results in the analysis of urinary PAH biomarkers, although covering all parameters initially selected was still too challenging.

Exposure to polycyclic aromatic hydrocarbons assessed by biomonitoring of firefighters during fire operations in Germany

BACKGROUND

Firefighters are exposed to a variety of hazardous substances including carcinogens such as polycyclic aromatic hydrocarbons (PAH) during firefighting. In order to minimize the uptake of such substances into the body, firefighters wear personal protective equipment. Only few data exist from real-life firefighting missions and under common although highly variable exposure scenarios such as fighting fires in residential buildings, outdoor, and vehicle fires. The aim of this study is to assess the levels of 1-Hydroxypyrene (1-OHP) as marker for incorporated PAH during firefighting operations in Germany using biomonitoring methods.

METHODS

We analyzed urine samples for 1-OHP from 77 firefighters who reported firefighting operations (with and without creatinine adjustment). Urine samples were collected before (baseline) and, where applicable, after firefighting operations at three time points subsequent (2-4, 6-8, and 12 h).

RESULTS

Compared to the baseline measurements, mean 1-OHP concentrations after firefighting missions were doubled (0.14 vs. 0.31 μg/L urine, 0.13 μg/g vs. 0.27 μg/g creatinine) and this increase was observed 2-4 h after firefighting. Firefighting in residential buildings (N = 54) and of outdoor and vehicle fires (N = 17) occurred most frequently, whereas blazes, vegetation fires, and fires in underground facilities (N = 6) were rarely encountered. For residential building fires, a 3-fold increase in mean 1-OPH concentrations was observed, whereas no increase could be observed for outdoor and vehicle fires. The highest increase was observed for firefighters with interior attack missions (0.11 μg/L vs. 0.48 μg/L 1-OHP) despite the use of self-contained breathing apparatus (SCBA). During the suppression of outdoor or vehicle fires using SCBA, again, no increase was observed. Although PAH are taken up during certain firefighting missions, the 1-OHP levels almost entirely remained (in 64 of the 77 reported missions) within the normal range of the German general population, i.e., below the reference levels (95th percentiles) of smokers (0.73 μg/g creatinine) and non-smokers (0.30 μg/g creatine).

CONCLUSION

Under study conditions, properly applied protective clothing and wearing of SCBA led to a significant reduction of PAH exposure levels. But there are individual situations in which PAH are increasingly incorporated since the incorporation depends on several factors and can be extremely variable. In contrast to many workplaces with high occupational exposure levels, firefighters are not exposed to PAH on a daily basis. Nevertheless, the possibility of an individual increased cancer risk for a particular firefighter cannot completely be ruled out.

Effectiveness of dermal cleaning interventions for reducing firefighters' exposures to PAHs and genotoxins

Firefighters are exposed to carcinogenic and mutagenic combustion emissions, including polycyclic aromatic hydrocarbons (PAHs). Fire service and firefighter cancer advocacy groups recommend skin cleaning using wipes or washing with detergent and water after exposure to smoke, although these strategies have not been proven to reduce exposures to harmful combustion products such as PAHs. This study assessed dermal decontamination methods to reduce PAH exposures by firefighters participating in live fire training scenarios. Study participants (n = 88) were randomly assigned to an intervention group (i.e., two types of commercial skin wipes, detergent and water, or a control group who did not use any skin decontamination). PAHs were measured in personal air (during the fire) and dermal wipe samples (before and after fire suppression and after dermal decontamination). PAH metabolites and mutagenicity were measured in urine samples before and after fire suppression. Airborne PAH concentrations during the fire ranged between 200 and 3,970 μg/m³ (mean = 759 μg/m³, SD = 685 μg/m³). Firefighters had higher total PAHs and high-molecular-weight PAHs on their skin after the fire compared to before (1.3- and 2.2-fold, respectively, p < 0.01). Urinary PAH metabolites increased significantly following exposure to the training fires by 1.7 to 2.2-fold (depending on the metabolite, p < 0.001). Urinary mutagenicity did not differ significantly between pre- and post-fire for any of the decontamination methods. Detergent and water was the only intervention that removed a significant amount of total PAHs from the skin (0.72 ng/cm² preintervention vs. 0.38 ng/cm² postintervention, p < 0.01). However, fold changes in urinary PAH metabolites (i.e., pre- vs. post-exposure levels) did not differ among any of the dermal decontamination methods or the control group. These data suggest that despite on-site attempts to remove PAHs from firefighters' skin, the examined interventions did not reduce the internal dose of PAHs. Future work should investigate preventing initial exposure using other interventions, such as improved personal protective equipment.

Phosphate-triggered ratiometric fluoroimmunoassay based on nanobody-alkaline phosphatase fusion for sensitive detection of 1-naphthol for the exposure assessment of pesticide carbaryl

The excessive use of carbaryl has resulted in the risk of its exposure. In this study, we isolated six nanobodies (Nbs) from a camelid phage display library against the biomarker of carbaryl, 1-naphthol (1-NAP). Owing to its characteristics of easy genetic modifications, we produced a nanobody-alkaline phosphatase (Nb-CC4-ALP) fusion protein with good stability. A dual-emission system based ratiometric fluoroimmunoassay (RFIA) for quick and highly sensitive determination of 1-NAP was developed. Silicon nanoparticles (SiNPs) was used as an internal reference and for aggregation-induced emission enhancement (AIEE) of gold nanoclusters (AuNCs), while AuNCs could be quenched by MnO2 via oxidation. In the presence of ALP, ascorbic acid phosphate (AAP) can be transformed into ascorbic acid (AA), the later can etch MnO2 to recover the fluorescence of the AuNCs. Based on optimal conditions, the proposed assay showed 220-fold sensitivity improvement in comparison with conventional monoclonal antibody-based ELISA. The recovery test of urine samples and the validation by standard HPLC-FLD demonstrated the proposed assay was an ideal tool for screening 1-NAP and provided technical support for the monitoring of carbaryl exposure.

Simultaneous analysis of PAH urinary mono- and dihydroxylated metabolites by GC-MS-MS following SPE and two-stage derivatization

A new gas chromatography-tandem mass spectrometry method for the determination of mono- and dihydroxylated polycyclic aromatic hydrocarbon metabolites (OH-PAHs and diol-PAHs) in urine was developed and validated. Various sample preparation procedures were compared, namely liquid-liquid extraction (LLE), dispersive solid-phase extraction (dSPE), and SPE, alone or combined. A novel two-stage derivatization approach using 2 silylation reagents was developed, and an experimental procedure design was used to optimize the programmed temperature vaporization-solvent vent injection (PTV-SV) GC parameters. The method focused on 11 target compounds resulting from four- to five-ring suspected carcinogenic PAHs. SPE was identified as an acceptable and more convenient extraction method for all tested metabolites, with extraction rates ranging from 63 to 86% and relative standard deviations lower than 20%. The two-stage derivatization approach successfully allowed first the derivatization of OH-PAHs by MTBSTFA (N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide) and then diol-PAHs by BSTFA (N,O-bis(trimethylsilyl)trifluoroacetamide) in a single run. The limits of quantification were in the range of 0.01-0.02 μg l^-1 for OH-PAHs and 0.02-0.2 μg l^-1 for diol-PAHs. The intra- and interday precisions were lower than 10%. The method was applied to determine PAH metabolites in urine collected at the beginning and at the end of the working week from 6 workers involved in aluminum production. The mean diol-PAH levels at the end of the week were 10 to 20 times higher (0.86-2.34 μg g^-1 creatinine) than those of OH-PAHs (0.03-0.30 μg g^-1). These results confirmed the usefulness of this new analytical technique for detecting and characterizing metabolic patterns of PAHs in urine and assessing carcinogenic occupational exposures.

PAHs and their hydroxylated metabolites in the human fingernails from e-waste dismantlers: Implications for human non-invasive biomonitoring and exposure

Non-invasive human biomonitoring methods using hair and fingernails as matrices are widely used to assess the exposure of organic contaminants. In this work, a total of 72 human fingernails were collected from workers and near-by residents from a typical electronic waste (e-waste) dismantling site, and were analyzed for human exposure to polycyclic aromatic hydrocarbons (PAHs) and their mono-hydroxyl metabolites (OH-PAHs). The concentrations of PAHs and OH-PAHs were obtained as 7.97-551 and 39.5-3280 ng/g for e-waste workers (EW workers), 7.05-431 and 27.3-3320 ng/g for non-EW workers, 7.93-289 and 124-779 ng/g for adult residents, and 8.88-1280 and 181-293 ng/g for child residents, respectively. The composition profiles of PAHs in the human fingernails of the four groups were similar, with isomers of Phe, Pyr and Fluo being the predominated congeners, while 2-OH-Nap accounted for more than 70% of the total OH-PAHs. These contaminants were found most in the fingernails of EW workers, followed by non-EW workers, adult residents, and child residents, indicating e-waste dismantling activities are the major sources of PAH exposure. However, significantly higher levels of PAHs with 4-6 rings were observed only in workers as opposed to the residents, and a significant correlation between 3-OH-Flu (p < 0.05) and 2-OH-Phe (p < 0.01) in the fingernails and urine was observed, but no significant correlation was found between the concentration of OH-PAHs in matched hair and fingernail samples. In addition, the levels of PAHs in fingernails increased with the age of EW workers. This is the first study to explore the accumulation and distribution of PAHs and OH-PAHs in human fingernails, which would provide valuable insight into non-invasive biomonitoring and health risk assessment of PAHs.

Co-exposure and health risks of parabens, bisphenols, triclosan, phthalate metabolites and hydroxyl polycyclic aromatic hydrocarbons based on simultaneous detection in urine samples from guangzhou, south China

Polycyclic aromatic hydrocarbons (PAHs) and certain ingredients in personal care products, such as parabens, bisphenols, triclosan and phthalate metabolites, have become ubiquitous in the world. Concerns of human exposure to these pollutants have increased during recent years because of various adverse health effects of these chemicals. Multiple compounds including parabens, bisphenols, triclosan, phthalate metabolites (mPAEs) and hydroxyl PAHs (OH-PAHs) in urine samples from Guangzhou were determined simultaneously to identify the human exposure pathways without external exposure data combined with data analysis, and the toxicants posed the highest risk to human health were screened in the present study. The detection frequencies for the chemicals exceeded 90%. Among the contaminants, mPAEs showed the highest concentrations, followed by OH-PAHs, with triclosan present at the lowest concentrations. Mono-n-butyl phthalate, methylparaben, bisphenol A, and hydroxynaphthalene represented the most abundant mPAE, parabens, bisphenol, and OH-PAH compounds, respectively. The present PAHs are mainly exposed to human through inhalation, while the chemicals added to personal care products are mainly exposed to human through oral intake and dermal contact. The urine samples from suburban subjects showed significantly higher OH-PAH levels than the urine samples from urban subjects, and females had lower OH-PAH levels than males. Urinary concentrations of the analyzed contaminants were significantly correlated with age, body mass index, residence time, as well as the frequencies of alcohol consumption and swimming. Risk assessments based on Monte Carlo simulation indicated that approximately 30% of the subjects suffered non-carcinogenic risks from mPAEs and OH-PAHs, with mPAEs accounting for 89% of the total risk.

The association of urinary metabolites of polycyclic aromatic hydrocarbons with obstructive coronary artery disease: A red alert for action

In Lebanon, previous studies have indicated an onset of cardiovascular diseases 12 years earlier than in other parts of the world, suggesting the presence of additional risk factors specific to Lebanon. Measurements of airborne particles in Lebanon surpass the recommendations of the World Health Organization by over 150%. This study examined the association between obstructive coronary artery disease (CAD), assessed by a novel marker calculated from coronary catheterization, and markers of air pollution, specifically polycyclic aromatic hydrocarbons (PAHs), in a cohort of 258 patients seen at the American University of Beirut Medical Center since 2014. The concentrations of four types of hydroxylated polycyclic aromatic hydrocarbons (OHPAHs), 2-OHNAP, 2-OHFLU, 3-OHPHE, and 1-OHPYR, were measured in the urine samples of these patients using high performance liquid chromatography coupled with fluorescence detector. Results showed that the OHPAH concentrations were higher than what was reported in high-income countries and, most notably, the levels for non-smokers in this study were higher than those of smokers and some occupational workers in other countries. This implies that patients were exposed to high levels of PAHs, which originate from combustion sources. In particular, 1-OHPYR showed a significant association with presence of obstructive CAD, even after adjusting for covariates like age, sex, and diabetes. Smokers or not, this association has implications for public health and calls for urgent need to pass regulations to reduce the emissions of PAH sources, such as cars, diesel generators, and incinerators.

The influence of demographic and lifestyle factors on urinary levels of PAH metabolites-empirical analyses of Cycle 2 (2009-2011) CHMS data

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds formed during the incomplete combustion of organic matter. Several are mutagenic carcinogens; the magnitude of exposure can be assessed by examining urinary levels of PAH metabolites. Data from biomonitoring studies that record urinary PAH metabolite levels, as well as demographic and lifestyle information, can be used to investigate relationships between PAH exposure and variables, such as smoking status, workplace smoking restrictions, age, sex, household income, home age, and occupation. This study analysed creatinine-adjusted urinary PAH metabolite concentrations and questionnaire data from ~1200 individuals aged 16 years and older surveyed in Cycle 2 of the Canadian Health Measures Survey (CHMS). Statistical analyses revealed that smoking status, age, and sex are associated with urinary concentrations of a pyrene metabolite (1-OHP), phenanthrene metabolites (ΣOH-Phen), fluorene metabolites (ΣOH-Flu) and naphthalene metabolites (ΣOH-Nap). More specifically, smoking status, age and sex can collectively account for 30, 24, 52, and 34% of the observed variations in 1-OHP, ΣOH-Phen, ΣOH-Flu and ΣOH-Nap metabolites, respectively (p < 0.001). Analyses of non-smokers revealed weak but significant effects of age, sex, home age, and occupation on urinary levels of selected PAH metabolites (i.e., <7% of observed variation, p < 0.05). The unexplained variation in PAH metabolite levels is most likely related to diet, which was not examined. Although the results revealed significant relationships between urinary PAH metabolite levels and several lifestyle and/or demographic variables, robust examinations of selected effects (e.g., sex, home age, occupation) will require datasets that are balanced with respect to the other highlighted variables. The results can be used to identify remedial measures to reduce exposure and concomitant risk, and/or design follow-up studies to test hypotheses regarding the causes of exposure differences empirically related to sex, age, home age, and occupation.

Determination of glyphosate, glufosinate and their major metabolites in urine by the UPLC-MS/MS method applicable to biomonitoring and epidemiological studies

The preoccupation concerning glyphosate (GLYP) has rapidly grown over recent years, and the availability of genetically modified crops that are resistant to GLYP or glufosinate (GLUF) has increased the use of these herbicides. The debate surrounding the carcinogenicity of GLYP has raised interest and the desire to gain information on the level of exposure of the population. GLYP and aminomethylphosphonic acid (AMPA) are commonly simultaneously analysed. GLUF is sometimes also monitored, but its major metabolite, 3-[hydroxy(methyl)phosphinoyl]propionic acid (3MPPA), is rarely present in the method. Using a pentafluorobenzyl derivative to extract the analytes from human urine, we present a method that contains four important analytes to monitor human exposure to GLYP and GLUF. The use of the flash freeze technique speeds up the extraction process and requires less organic solvent than conventional liquid-liquid extraction. The limits of detection in the low μg/L range enable the use of this method for epidemiological studies. The results obtained for 35 volunteers from the Quebec City area are presented with the results from multiple interlaboratory comparisons (G-EQUAS, HBM4EU and OSEQAS). This methodology is currently being used in the Maternal-Infant Research on Environmental Chemicals (MIREC-ENDO) study and in the Canadian Health Measures Survey (CHMS).

Cross-validation of biomonitoring methods for polycyclic aromatic hydrocarbon metabolites in human urine: Results from the formative phase of the Household Air Pollution Intervention Network (HAPIN) trial in India

The Household Air Pollution Intervention Network (HAPIN) trial is evaluating health benefits of a liquefied petroleum gas (LPG) stove intervention in biomass cook-fuel using homes (n = 3200) in four low-and middle-income countries (LMICs) that include Peru, Guatemala, Rwanda and India. Longitudinal urine samples (n = 6000) collected from enrolled pregnant women, infants and older women will be analyzed for biomarkers associated with exposure and health outcomes. We report results from cross-validation of a lower cost high-performance liquid chromatography with fluorescence detection (HPLC-FLD) method with a higher resolution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the measurement of 1-hydroxypyrene (1PYR) and 2-naphthol (2NAP). Twenty-five split urine samples were analyzed by HPLC-FLD method at the India trial site in Chennai, India and by LC-MSMS method at the trial wide Biomarker Coordinating Center, Emory University, USA. The limits of detection (LOD) for the HPLC-FLD method were 0.02 ng/mL and 0.07 ng/mL for 2NAP and 1PYR, respectively. Bland-Altman analysis estimated a bias of 2.98 ng/ml for 2NAP (95% CI: -5.22, -0.75) and 0.09 ng/mL for 1PYR (95% CI: -0.02, 0.21) with HPLC-FLD levels being lower than LC-MSMS levels at higher concentrations. Analyses of additional urine samples (n = 119) collected during the formative phase of the HAPIN trial in India, showed 2NAP and 1PYR levels to be consistently above the limit of quantification (LOQ) and demonstrated the applicability of the method. The HPLC-FLD method can serve as a cost-effective and reliable analytical method to measure 2NAP and 1PYR in human urine in LMICs, within and beyond the HAPIN trial.

Rapid Screening of Urinary 1-Hydroxypyrene Glucuronide by Multisegment Injection-Capillary Electrophoresis-Tandem Mass Spectrometry: A High-Throughput Method for Biomonitoring of Recent Smoke Exposures

Urinary 1-hydroxypyrene (HP) is a widely used biomarker of polycyclic aromatic hydrocarbon exposure relevant for biomonitoring the deleterious health impacts from tobacco smoke and ambient air pollution, as well as the hazards of certain occupations. Conventional methods for urinary HP analysis based on liquid chromatography with native fluorescence detection or tandem mass spectrometry (MS/MS) and gas chromatography-mass spectrometry (GC-MS) are limited by low sample throughput and complicated sample workup protocols that are prone to bias. Herein, we introduce a high throughput method to directly analyze the intact glucuronide conjugate of HP (HP-G) in human urine after a simple acidified ether extraction procedure when using multisegment injection-capillary electrophoresis-tandem mass spectrometry (MSI-CE-MS/MS). Multiplexed analyses of 13 independent urine extracts are achieved in a single run (<3 min/sample) with stringent quality control while avoiding enzyme deconjugation and precolumn chemical derivatization. Method validation demonstrates good technical precision (CV = 7.7%, n = 45) and accuracy with a mean recovery of (93 ± 3%) for urinary HP-G at three concentration levels with adequate detection limits (7 ng/L, S/N = 3). An interlaboratory method comparison of urine samples collected from firefighters deployed in the 2016 Fort McMurray wildfire also confirms good mutual agreement with an acceptable negative bias (mean bias = 15%, n = 55) when measuring urinary HP-G by MSI-CE-MS/MS as compared to total hydrolyzed urinary HP by GC-MS due to the low residual levels of free HP and its sulfate conjugate. This multiplexed separation platform is optimal for large-scale biomonitoring studies of air pollution relevant to global health as well as occupational smoke exposures in firefighters susceptible to dermal PAH absorption when using personal protective equipment.

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.

Fast magnetic solid-phase extraction using an Fe3O4-NH2@MOF material for monohydroxy polycyclic aromatic hydrocarbons in urine of coke-oven workers

In this work, a magnetic material (Fe3O4-NH2@MIL-101) was successfully prepared, and the material was used as a sorbent for the magnetic solid-phase extraction (MSPE) of trace level monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) from urine samples for the first time. The target analytes were quantified by high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD). The MSPE key factors, which include the amount of adsorbent, extraction time, pH, the effect of salt, eluting solutions and eluant volume, were systematically optimized. Under the optimized conditions, the developed method showed good linearity (0.03-200 ng mL-1), low limits of detection (0.016-0.042 ng mL-1, signal-to-noise ratio = 3) and satisfactory repeatability (relative standard deviation ≤ 10.1%, n = 5). The method showed stable average recoveries ranging from 78.3% to 112.9% and the enrichment factors were 9 to 15. Besides the satisfactory method parameters, the total MPSE process could be completed in no more than 5 minutes. These results indicated that Fe3O4-NH2@MOF based MSPE was a simple, efficient and fast method which was suitable for MSPE of OH-PAHs from urine samples.

Polycyclic aromatic hydrocarbons (PAHs) levels in urine samples collected in a subarctic region of the Northwest Territories, Canada

Traditional food consumption for Indigenous peoples is associated with improved nutrition and health but can also pose potential risks via exposure to contaminants. Polycyclic aromatic hydrocarbons (PAHs) are compounds of interest due to their widespread presence (e.g., their metabolites are detected in up to 100% of the Canadian population) and their toxicological potential. To better understand the range of exposures faced by Indigenous populations in northern Canada and to address a contaminant of emerging concern identified by the Arctic Monitoring and Assessment Programme, a multi-year biomonitoring study investigated levels of PAH exposure in subarctic First Nations communities of the Northwest Territories, Canada. Secondary data analysis of banked samples from a subset of the cross-sectional study was done. PAHs and cotinine markers in the urine samples (n = 97) of participants from two regions from the Mackenzie Valley (Dehcho and Sahtú) was completed by liquid and gas chromatography coupled with mass spectrometry. Also, participants completed a 24-hr recall food survey. When compared according to age/sex categories, the GM of several biomarkers (1-hydroxypyrene, 1-naphthol, 2-hydroxyfluorene, 2-hydroxyphenanthrene, 2-naphthol, 3-hydroxyfluorene, 3-hydroxyphenanthrene, 4-hydroxyphenanthrene, 9-hydroxyfluorene, 9-hydroxyphenanthrene) appeared higher than observed for the general Canadian population. The PAHs levels observed were, however, below clinical levels associated with adverse health outcomes. Altogether, these elevated biomarkers are metabolites of pyrene, naphthalene, fluorene and phenanthrene. Statistically significant non-parametric associations were observed between several biomarkers and i) the consumption of cooked meat in the last 24 h; and, ii) smoking status (self-reported status and adjusted on urine cotinine level). This work is the first to report PAH levels in a northern Canadian population and provides local baseline data for monitoring the effects of changes to climate and lifestyle over time. These findings will support regional and territorial decision makers in identifying environmental health priorities.

Insights into biomonitoring of human exposure to polycyclic aromatic hydrocarbons with hair analysis: A case study in e-waste recycling area

In this study, 96 pairs of hair and urine samples were collected from e-waste (EW) dismantling workers of an industrial park, as well as residents living in surrounding areas. The concentrations of polycyclic aromatic hydrocarbons (PAHs) and hydroxylated PAH metabolites (OH-PAHs) were analyzed . The results show that concentrations of Σ₁₅PAHs ranged from 6.24 to 692 ng/g dry weight (dw) and Σ₁₂OH-PAHs from undetected to 187 ng/g dw in hair external (hair-Ex), and ranged from 31.7 to 738 ng/g dw and 21.6 to 1887 ng/g dw in hair internal (hair-In). There was no significant difference in exposure levels between EW dismantling workers and residents of the surrounding area. For the parent PAHs, the concentrations of Σ₁₅PAHs of hair-In were comparable with those of hair-Ex for all populations except for the child residents. On the contrary, for the OH-PAHs, the concentrations of Σ₁₂OH-PAHs of hair-In were 9-37 times higher than those of hair-Ex for populations. Moreover, the congener profiles of OH-PAHs of hair-In were different from those of hair-Ex, but similar to that of urine. Particularly, 3-OH-Bap, which is a carcinogenic metabolite, was only detected in the hair-In. These results indicate that OH-PAHs in hair-In, just like in urine, are mainly derived from endogenous metabolism and could be considered as reliable biomarkers for PAHs exposure. However, there was almost no significant correlations between hair-In and urine for OH-PAHs. This indicates that more attention should be paid to OH-PAHs when conducting PAHs exposure risk assessment using hair, which will help to obtain more reliable and comprehensive information on health risk assessments.

Analysis of urinary metabolites of polycyclic aromatic hydrocarbons and cotinine in pooled urine samples to determine the exposure to PAHs in an Australian population

Our previous biomonitoring study of hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) in a population in Australia found high levels of 1-naphthol, a metabolite of both naphthalene and carbaryl, in some adult samples. Here, we conducted a follow-up study to collect and analyse pooled urine samples, stratified by age and sex, from 2014 to 2017 using a GC-MS method. Geometric mean concentrations of 1-hydroxypyrene, the most common biomarker of PAH exposure, were 100 and 120 ng/L urine in 2014-2015 and 2016-2017, respectively. The concentrations of most OH-PAHs in this study except 1-naphthol are in line with those reported by biomonitoring programs in the US and Canada. In general, concentrations of OH-PAHs are lower in samples from small children (0-4 years) and school-aged children (5-14 years) compared with samples from the older age groups, except for some cases in the recent monitoring period. The concentrations of 1-naphthol in some adult samples of both sexes are very high, which is consistent with our previous findings. Such high concentrations of 1-naphthol together with the high 1-naphthol/2-naphthol ratio suggest potential exposure to the insecticide carbaryl in this population but other exposure sources and different rates of naphthalene metabolism should also be investigated.

Urinary biomarkers of polycyclic aromatic hydrocarbons and the association with hearing threshold shifts in the United States adults

Polycyclic aromatic hydrocarbons (PAHs) are regarded as environmental pollutants that contribute to several adverse health outcomes. There is no research evidence to support a connection between PAH exposure and hearing loss. Our study aimed to determine the association between PAH exposure and hearing threshold shifts using the National Health and Nutrition Examination Survey (NHANES) dataset. A cross-sectional study was conducted among 1,071 US adults participating in the NHANES from 2001 to 2004. The association between PAH metabolites and the log-transformed hearing threshold was investigated using multivariate regression models, which included log-transformed, low-frequency and high-frequency thresholds. After additional pertinent adjustments, a positive correlation between PAH metabolite concentration and log-transformed hearing thresholds was observed. Individuals in the fourth quartile of PAH metabolite concentration had higher hearing thresholds compared with those in the first quartile of PAH metabolite concentration. Exposure to PAHs is related to hearing threshold shift at both low and high frequencies in the US adult population.

Determination of Urinary Hydroxyl PAHs Using Graphene Oxide@Diatomite Based Solid-Phase Extraction and High-Performance Liquid Chromatography

A diatomite supported graphene oxide composite (GO@Dt–NH₂) was fabricated and explored as a solid-phase extraction adsorbent coupled with high performance liquid chromatography to determine the trace hydroxyl polycyclic aromatic hydrocarbons (2-hydroxy-naphthalene, 2-hydroxy-fluorene, 1-hydroxy-phenanthrene, and 1-hydroxy-pyrene) in urine samples. The fabricated composites were characterized by X-ray powder diffractometry and scanning electron microscopy. GO@Dt–NH₂ offered enhanced adsorption affinity towards the analytes compared with the bare diatomite. The amount of graphene oxide and the factors affecting solid-phase extraction were investigated in detail. Under the optimized conditions, the method gave good linearity (0.30–200 ng/mL) and a low detection limit (0.10–0.15 ng/mL) for the hydroxyl polycyclic aromatic hydrocarbons. The average recovery for spiked urine samples with three levels ranged from 90.6% to 100%. The intra-day and inter-day relative standard deviations were in the range of 1.8–6.4% and 2.7–11.8%, respectively. Besides, the GO@Dt–NH₂ provided enrichment factors of 18–20 and superior purification ability. The developed method was successfully applied to the determination of hydroxyl polycyclic aromatic hydrocarbons in urine samples from smoking volunteers.

Urinary metabolites of polycyclic aromatic hydrocarbons in pregnant women and their association with a biomarker of oxidative stress

Exposure to polycyclic aromatic hydrocarbons (PAHs) during pregnancy may pose adverse health risk to both the mothers and babies. In the present study, 188 pregnant women of different trimesters were recruited in Guangzhou, south China, and nine hydroxyl PAHs (OH-PAHs) and a biomarker of DNA oxidative damage, 8-hydroxy-2'-deoxyguanosine (8-OHdG), were determined in their urine samples. All OH-PAHs except for 4-hydroxyphenanthrene and 6-hydroxychrysene were found in > 90% samples, with total concentration in the range of 0.52 to 42.9 μg/g creatinine. In general, concentration levels of OH-PAHs in pregnant women were lower than those in general population in the same research area but with higher levels in working women than in housewives. The mean daily intakes of PAHs from dietary estimated by urinary OH-PAHs were 0.021, 0.004, 0.047, and 0.030 μg/kg_bw/day for naphthalene, fluorene, phenanthrene, and pyrene, respectively, which were much lower than the reference doses (20, 30, and 40 μg/kg_bw/day for naphthalene, pyrene, and fluorene, respectively) derived from chronic oral exposure data by the United States Environmental Protection Agency. The low exposure levels of PAHs may be attributed to the traditional dietary taboo of Chinese pregnant women, which is to minimize the consumption of "toxic" food. The concentrations of 8-OHdG (4.67-49.4 μg/g creatinine) were significantly positively correlated with concentrations of several OH-PAHs, such as metabolites of naphthalene, fluorene, and phenanthrene (r = 0.3-0.6). In addition, the concentrations of 8-OHdG were higher in working women than in housewives when exposed to the same levels of PAHs, partly indicating the possible relation between work-related pressure for working women and the oxidative stress.

Supported-liquid phase extraction in combination with isotope-dilution gas chromatography triple quadrupole tandem mass spectrometry for high-throughput quantitative analysis of polycyclic aromatic hydrocarbon metabolites in urine

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants with a number of them being carcinogenic. One of the approaches to assess human exposure to PAHs is to measure their urinary metabolites, monohydroxyl polycyclic aromatic hydrocarbons (OH-PAHs), with a method allowing for high throughput and short turn-around time. We developed a method to quantify nine urinary OH-PAHs by using supported liquid phase extraction (SLE) and isotope dilution gas chromatography tandem mass spectrometry (GC-MS/MS). SLE demonstrated advantages over the traditionally used liquid-liquid extraction techniques. The target analytes with spiked deuterated and ¹³C-labeled internal standards were extracted from urine by SLE after enzymatic cleavage of the glucuronide and sulfate conjugates. The extracted analytes were then derivatized with N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), and analyzed by GC-MS/MS. Six solvent mixtures were evaluated as the SLE extraction solvent, and pentane:chloroform (7:3, v/v) was selected due to its best overall analytical performance. Method detection limits for the 9 analytes ranged from 2.3 to 13.8 pg/mL. Precision and accuracy were satisfactory. SLE and internal isotope labeled standard combination reduced matrix effect effectively. This new method using SLE sample preparation techniques coupled with GC-MS/MS proves applicable to urinary measurements for PAH exposure studies for general population.

Implementation of human biomonitoring in the Dehcho region of the Northwest Territories, Canada (2016-2017)

Background

Human biomonitoring represents an important tool for health risk assessment, supporting the characterization of contaminant exposure and nutrient status. In communities where country foods (locally harvested foods: land animals, fish, birds, plants) are integrated in the daily diet, as is the case in remote northern regions where food security is a challenge, such foods can potentially be a significant route of contaminant exposure. To assess this issue, a biomonitoring project was implemented among Dene/Métis communities of the Dehcho region of the Northwest Territories, Canada.

Methods

Participants completed dietary surveys (i.e., a food frequency questionnaire and 24-h recall) to estimate food consumption patterns as well as a Health Messages Survey to evaluate the awareness and perception of contaminants and consumption notices. Biological sampling of hair, urine and blood was conducted. Toxic metals (e.g., mercury, lead, cadmium), essential metals (e.g., copper, nickel, zinc), fatty acids, and persistent organic pollutants (POPs) were measured in samples.

Results

The levels of contaminants in blood, hair and urine for the majority of participants were below the available guidance values for mercury, cadmium, lead and uranium. However, from the 279 participants, approximately 2% were invited to provide follow up samples, mainly for elevated mercury level. Also, at the population level, blood lead (GM: 11 μg/L) and blood cadmium (GM: 0.53 μg/L) were slightly above the Canadian Health Measures Survey data. Therefore, although country foods occasionally contain elevated levels of particular contaminants, human exposures to these metals remained similar to those seen in the Canadian general population. In addition, dietary data showed the importance and diversity of country foods across participating communities, with the consumption of an average of 5.1% of total calories from wild-harvested country foods.

Conclusion

This project completed in the Mackenzie Valley of the Northwest Territories fills a data gap across other biomonitoring studies in Canada as it integrates community results, will support stakeholders in the development of public health strategies, and will inform environmental health issue prioritization.

Electronic supplementary material

The online version of this article (10.1186/s13690-018-0318-9) contains supplementary material, which is available to authorized users.

[Human Biomonitoring as a Useful Approach to Health Risk Assessment Compared with Occupational Exposure Assessment of Insecticide Intake: Fundamental Study Focused on Local Populations and Occupational Fields]

Human biomonitoring (HBM) is a technique to evaluate chemical exposure level by measuring the levels of chemicals or related substances such as their metabolites or adducts in biological samples (e.g., urine or blood). Compared with exposure assessment by an approach to estimate insecticide intake from diet or the environment, HBM can provide information more specific to an individual exposure dose and can reflect the exact body burden condition at the time of measurement. If the analytical sensitivities, completeness and cost-effectiveness of the method are improved further, HBM might be widely applicable to not only research fields such as epidemiological and occupational study but also routine analysis for effective prevention of the exposure of the human body to chemical substances. In this article, we provide an overview of HBM as a determination method for insecticide exposure markers in urine and its applications, and discuss future research perspectives in the field of environmental and occupational health.

New approach for the determination of ortho-phenylphenol exposure by measurement of sulfate and glucuronide conjugates in urine using liquid chromatography-tandem mass spectrometry

Ortho-phenylphenol (OPP) has been widely used as a fungicide and preservative. Although low-dose studies have demonstrated its low toxicity in animals and humans, high-dose exposure to this contaminant has toxic effects that range from skin irritation to bladder cancer. Thus far, monitoring of OPP exposure in the general population has been performed by measuring OPP after urine hydrolysis with the β-glucuronidase/arylsulfatase enzyme and sometimes by the use of a mineral acid. We developed a sensitive, accurate, and robust method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to specifically measure two-phase II OPP metabolites excreted in human urine, OPP sulfate (OPP-S), and OPP glucuronide (OPP-G). Comparative analysis of urine samples from 50 volunteers living in the Quebec City area using a direct method and phosphoric acid hydrolysis method previously developed in our laboratory showed no statistically significant difference (p value for paired t test = 0.701) in OPP concentrations. Moreover, a significant difference showed that underestimation (p value for paired t test = 0.025) occurs when β-glucuronidase/arylsulfatase enzyme deconjugation is used. The LOD achieved by the direct method permits the detection of OPP-S and OPP-G metabolites in urine at the submicrogram per liter level. Graphical abstract ᅟ.

Elevated Exposures to Polycyclic Aromatic Hydrocarbons and Other Organic Mutagens in Ottawa Firefighters Participating in Emergency, On-Shift Fire Suppression

Occupational exposures to combustion emissions were examined in Ottawa Fire Service (OFS) firefighters. Paired urine and dermal wipe samples (i.e., pre- and post-event) as well as personal air samples and fire event questionnaires were collected from 27 male OFS firefighters. A total of 18 OFS office workers were used as additional controls. Exposures to polycyclic aromatic hydrocarbons (PAHs) and other organic mutagens were assessed by quantification of urinary PAH metabolite levels, levels of PAHs in dermal wipes and personal air samples, and urinary mutagenicity using the Salmonella mutagenicity assay (Ames test). Urinary Clara Cell 16 (CC16) and 15-isoprostane F_2t (8-iso-PGF_2α) levels were used to assess lung injury and overall oxidative stress, respectively. The results showed significant 2.9- to 5.3-fold increases in average post-event levels of urinary PAH metabolites, depending on the PAH metabolite (p < 0.0001). Average post-event levels of urinary mutagenicity showed a significant, event-related 4.3-fold increase (p < 0.0001). Urinary CC16 and 8-iso-PGF_2α did not increase. PAH concentrations in personal air and on skin accounted for 54% of the variation in fold changes of urinary PAH metabolites (p < 0.002). The results indicate that emergency, on-shift fire suppression is associated with significantly elevated exposures to combustion emissions.

Reliable quantification of 1,2-dihydroxynaphthalene in urine using a conjugated reference compound for calibration

After environmental and occupational exposure to naphthalene, 1,2-dihydroxynaphthalene (1,2-DHN) was shown to be one major metabolite in human naphthalene metabolism. However, the instability of free 1,2-DHN complicates the reliable determination of this promising biomarker in urine. To solve this stability problem, glucuronide conjugates of 1,2-DHN and the corresponding isotopically labelled D₆-1,2-dihydroxynaphthalene (D₆-1,2-DHN) were synthesised and applied as reference material and internal standard in a gas chromatographic-tandem mass spectrometric (GC-MS/MS) method. The determination of 1- and 2-naphthol (1-MHN, 2-MHN) was included in the procedure to enable a comprehensive assessment of naphthalene metabolism and exposure. The results of the validation showed a high reliability and sensitivity of the method. The detection limits range from 0.05 to 0.16 μg/L. Precision and repeatability were determined to range from 1.4 to 6.6% for all parameters. The simultaneous determination of 1- and 2-MHN as additional parameters besides 1,2-DHN enables the application of the method for further metabolism and kinetic studies on naphthalene. The use of glucuronide-derivative reference substances and the application of structurally matched isotopic-labelled internal standards for each substance guarantee a reliable quantification of the main naphthalene metabolites 1,2-DHN and 1- and 2-MHN. Graphical abstract Reliable quantification of 1,2-dihydroxynaphthalene in urine using a conjugated reference compound for calibration.