Human biomonitoring reference values for some non-persistent chemicals in blood and urine derived from the Canadian Health Measures Survey 2009–2013

Development of a non-separative screening strategy based on mass spectrometry for the semi-quantification of urinary polycyclic aromatic hydrocarbon metabolites

A fast and non-separative screening strategy is presented for the analysis of five urinary metabolites of polycyclic aromatic hydrocarbons (PAHs), namely 2-naphthol, 1-acenaphthenol, 2-hydroxyfluorene, 9-phenanthrol and 1-hydroxypyrene. These hydroxylated derivatives (OH-PAHs) were subjected to enzymatic hydrolysis and were extracted from urine using a liquid-liquid extraction (LLE). The profile signals were obtained by direct injection of the sample into a programmed temperature vaporizer coupled to a quadrupole mass spectrometer via a deactivated fused silica tubing (PTV-qMS). Semi-quantitative determination was carried out by means of partial least squares regression (PLS1) using urine samples free of the analytes and spiked at several uncorrelated concentration levels. The multivariate calibration models worked satisfactorily, with errors ranging between 30 and 33 % for all the analytes except for 1-acenaphthenol that provided an error of 39 % when external validation set was considered. The repeatability and reproducibility, expressed as relative standard deviation (RSD), were ranged between 8-16 % and 11-18 %, respectively. The proposed method could be a useful tool for semi-quantification purposes of five OH-PAHs in urine samples, identifying positive samples for subsequent further chromatographic separation (confirmation), thus saving time and costs.

Mass spectrometry detection of organophosphorus pesticide adducts on butyrylcholinesterase and albumin

This study established a method to prepare and detect OPs adducts on butyrylcholinesterase (BChE) and human serum albumin (HSA). OPs (methyl paraoxon, ethyl paraoxon, methyl parathion, parathion) were incubated with BChE or HSA in vitro, and the adducts of OPs-BChE or OPs-HSA were prepared and qualitatively analyzed by ultra-performance liquid chromatography data-dependent high-resolution tandem mass spectrometry (UPLC-ddHRMS/MS). The amounts of BChE and HSA in the incubating systems were varied and the resulting amounts of the adducts were determined using linear regression. OPs-BChE in the blood were isolated by immunomagnetic separation (IMS), and then digested into the OPs-nonapeptide adduct by pepsin. The proteins in the remaining blood plasma were precipitated and digested by pronase to OPs-tyrosines(OPs-Tyr), which were quantified by UPLC-ddHRMS/MS. 4 OPs-nonapeptides and 4 OPs-Tyr adducts were obtained through the process above. The relative mass deviation of incubated adducts between the actual and theoretical exact masses was less than 10 ppm, and further confirmed by fragmentation mass spectra analysis. Calibration curves were linear for all adducts with a coefficient of determination value (R2) ≥0.995. The limits of detection (LOD) and limits of quantification (LOQ) for adducts detected by MS ranged from 0.05 to 1.0 ng/mL, and from 0.1 to 2.0 ng/mL, respectively. The recovery percentages for adducts ranged from 76.1 % to 107.1 %, matrix effects ranged from 83.4 % to 102.1 %. The inter-day and intra-day precision were 6.1-10.1 % and 6.9-12.9 % for adducts. This study provides a new reference method for the detection of organophosphorus pesticide poisoning. In addition, two blood samples with organophosphorus poisoning were tested by the designed method, and the corresponding adducts were detected in both samples.

Association between Environmental Exposure to Multiclass Organic Pollutants and Sex Steroid Hormone Levels in Women of Reproductive Age

Organic pollutant exposure may alter sex steroid hormone levels in both animals and humans, but studies on mixture effects have been lacking and mainly limited to persistent organic pollutants, with few hormones being investigated. Moreover, measurements from a single blood or urine sample may not be able to reflect long-term status. Using hair analysis, here, we evaluated the relationship between multiclass organic pollutants and sex steroid hormones in 196 healthy Chinese women aged 25-45 years. Associations with nine sex steroid hormones, including progesterone, androstenedione (AD), testosterone (T), estrone (E1), and 17β-estradiol (E2), and eight related hormone ratios were explored on 54 pollutants from polychlorinated biphenyl (PCB), pesticide, and bisphenol families using stability-based Lasso regression analysis. Our results showed that each hormone was associated with a mixture of at least 10 examined pollutants. In particular, hair E2 concentration was associated with 19 pollutants, including γ-hexachlorocyclohexane, propoxur, permethrin, fipronil, mecoprop, prochloraz, and carbendazim. There were also associations between pollutants and hormone ratios, with pentachlorophenol, dimethylthiophosphate, 3-phenoxybenzoic acid, and flusilazole being related to both E1/AD and E2/T ratios. Our results suggest that exposure to background levels of pesticides PCB180 and bisphenol S may affect sex steroid hormone homeostasis among women of reproductive age.

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.

Residue levels of organophosphate pesticides and dialkylphosphates in agricultural products in Japan

High urinary levels of dialkylphosphates (DAPs), which are common structures of organophosphate pesticides (OPs), have been associated with several adverse health outcomes in human biomonitoring studies. Previous studies have indicated that dietary OP exposure and ingestion of environmentally degraded DAP, which is inactive with acetylcholinesterase, can lead to an increase in urinary DAP levels in the general population. However, the specific food sources contributing to the intake of OPs and DAPs have not been identified. In this study, we analyzed the levels of OPs and preformed DAPs in various food items. DAP levels were markedly high in certain fruits, such as persimmon, apple juice, kiwi, and mandarin. In contrast, only moderate levels of OPs were detected in these foods. Furthermore, the levels of OPs and DAPs were positively associated with vegetables, whereas no such association was observed in fruits. Increased consumption of certain fruits presumably leads to a marked increase in urinary DAP levels in individuals despite limited exposure to OPs, resulting in reduced reliability of urinary DAPs as a marker of OP exposure. Therefore, the possible effects of dietary habits and the resulting intake of preformed DAPs should be considered when interpreting biomonitoring data of urinary DAPs. Additionally, DAP levels in most organic foods were much lower than those in conventional foods, suggesting that the reduction in urinary DAPs by organic diet intervention may be mainly attributed to the reduced intake of preformed DAPs rather than reduced exposure to OPs. Therefore, urinary DAP levels may not be suitable indicators for evaluating ingested OP exposure.

A revised concept for deriving reference values for internal exposures to chemical substances and its application to population-representative biomonitoring data in German children and adolescents 2014-2017 (GerES V)

HBM reference values, in contrast to toxicologically derived values, are statistically derived values that provide information on the exposure of the population. The exceedance frequency (if applicable for individual population groups) is often a first assessment standard for the local exposure situation for municipalities. More than 25 years have passed since the German Human Biomonitoring Commission (HBMC) formulated the first recommendations for the derivation of population-based reference values (HBM reference values, RV95) for substance concentrations based on HBM studies. A fundamental revision is timely, for several reasons. There have been considerable advances in relevant statistical methods, which meant that previously time-consuming and inaccessible procedures and calculations are now widely available. Furthermore, not all steps for the derivation of HBM reference values were clearly elaborated in the first recommendations. With this revision we intended to achieve a rigorous standardization of the entire process of deriving HBM reference values, also to realise a higher degree of transparency. In accordance with established international practice, it is recommended to use the 95th percentile of the reference distribution as the HBM reference value. To this end, the empirical 95th percentile of a suitable sample should be rounded, ensuring that the rounded value is within the two-sided 95% confidence interval of the percentile. All estimates should be based on distribution-free methods, and the confidence interval should be estimated using a bootstrap approach, if possible, according to the BCa ("bias-corrected and accelerated bootstrap"). A minimum sample size of 80 observations is considered necessary. The entire procedure ensures that the derived HBM reference value is robust against at least two extreme values and can also be used for underlying mixed distributions. If it is known in advance that certain subgroups (different age groups, smokers, etc.) show differing internal exposures, it is recommended that group-specific HBM reference values should be derived. Especially when the sample sizes for individual subgroups are too small, individual datasets with potential outliers can be excluded in advance to homogenize the reference value population. In the second part, new HBM reference values based on data of the German Environmental Survey for Children and Adolescents (GerES V, 2014-2017) were derived in accordance with the revised recommendations. The GerES V is the most recent population-representative monitoring of human exposure to pollutants in Germany on children and adolescents aged 3-17 years (N = 2294). RV95 for GerES V are reported for four subgroups (males/females and 3-11/12-17 years) for 108 different substances including phthalates and alternative plasticisers, metals, organochlorine pesticides, polychlorinated biphenyls (PCB), per- and polyfluoroalkyl substances (PFAS), parabens, aprotic solvents, chlorophenols, polycyclic aromatic hydrocarbons (PAH) and UV filter, in total 135 biomarkers. Algorithms implemented in R were used for the statistics and the determination of the HBM reference values. To facilitate a quality control of the study data, the corresponding R source code is given, together with graphical representations of results. The HBM reference values listed in this article replace earlier RV95 values derived by the HBMC for children and adolescents from data of precedent GerES studies (e.g. published in Apel et al., 2017).

Analysis of growth performance and carcass and meat quality of different crossbreeds of Cherry Valley duck

Duck breeding and production are facing great opportunities in China, as the market for small-sized high-quality duck is rapidly expanding. Therefore, breeding the most suitable genetic stock has become an important goal.This study assessed body and carcass weight, slaughter rate and meat quality of offspring of three cross combinations; Cherry Valley duck (CV♂) × Small-sized Pekin duck (PK♀), CV♂×Taiwan white duck (TW♀), CV♂×Putian white duck (PT♀) and the corresponding pure lines at 56 d of age. These 420 ducks were raised in seven separate groups (10 pens/group, 3♂+3♀/pen).Body and carcass weights were significantly lower in the three cross combinations than CV ducks (P=0.042 and P=0.012). Abdominal fat and sebum weight were lowest in CV♂×PK♀, whereas the breast and the leg muscle weights were significantly higher in CV♂×PK♀ compared to CV♂×TW♀ and CV♂×PT♀ (P=0.018 and P=0.023). No difference was observed in the visceral tissues among the three cross combinations or compared to CV ducks.The performance indicators suggested that CV♂×PK♀, CV♂×TW♀ and CV♂×PT♀ cross combinations are best suited for segmented duck meat, featured duck meat and whole-duck processing, respectively.

Medical devices used in NICU: The main source of plasticisers' exposure of newborns

Phthalates and other plasticisers are extensively used in medical devices (MD) from which they can leach out and lead to potential multiple problems for the patients. This exposure is a major issue because it is associated with reproductive and neurodevelopment disorders. The Neonatal Intensive Care Units (NICU) population is at high risk due to the daily intensive medical interventions, the reduced ability of newborns to remove these contaminants and their higher sensitivity to endocrine disruptors. We conducted a multicentric biomonitoring study to assess and compare the urinary levels of DEHP (di-(2-ethylhexyl)phthalate), DEHTP (di-(2-ethylhexyl)terephthalate) and TEHTM (tri-(2-ethylhexyl)trimellitate) metabolites as biomarkers of this exposure during and after the newborns' stay in NICU. Daily urinary samples were collected in NICU and at discharge from the hospital for each patient. MD sources and exposure factors were also investigated. 508 urinary samples from 97 patients enrolled in centres 1 and 2 (C1/C2) were collected. The exposure of newborns to DEHP was greater than that of DEHTP and TEHTM, with a median concentration of DEHP metabolites (C1:195.63 ng/mL;C2:450.87 ng/mL) respectively 5 to 10 times higher and 57 to 228 times higher than the median concentrations of DEHTP and TEHTM metabolites. The urinary concentrations of DEHP and TEHTM metabolites were significantly lower at discharge than in NICU, with a 18-and 35-fold decrease for DEHP and a 4 and 8-fold decrease for TEHTM, respectively for C1 and C2, but were similar for DEHTP metabolites. MD used for respiratory assistance, infusion therapy,enteral nutrition and transfusion were the main sources of exposure. Smaller gestational age and body weight significantly increased the newborns' exposure. The elevated levels of DEHP metabolites in NICU patients are still alarming. Additional efforts are necessary to promote its substitution in MD by possibly safer alternatives such as TEHTM and DEHTP, particularly when used for the care of newborns.

Literature review and evaluation of biomarkers, matrices and analytical methods for chemicals selected in the research program Human Biomonitoring for the European Union (HBM4EU)

Humans are potentially exposed to a large amount of chemicals present in the environment and in the workplace. In the European Human Biomonitoring initiative (Human Biomonitoring for the European Union = HBM4EU), acrylamide, mycotoxins (aflatoxin B1, deoxynivalenol, fumonisin B1), diisocyanates (4,4'-methylenediphenyl diisocyanate, 2,4- and 2,6-toluene diisocyanate), and pyrethroids were included among the prioritized chemicals of concern for human health. For the present literature review, the analytical methods used in worldwide biomonitoring studies for these compounds were collected and presented in comprehensive tables, including the following parameter: determined biomarker, matrix, sample amount, work-up procedure, available laboratory quality assurance and quality assessment information, analytical techniques, and limit of detection. Based on the data presented in these tables, the most suitable methods were recommended. According to the paradigm of biomonitoring, the information about two different biomarkers of exposure was evaluated: a) internal dose = parent compounds and metabolites in urine and blood; and b) the biologically effective = dose measured as blood protein adducts. Urine was the preferred matrix used for deoxynivalenol, fumonisin B1, and pyrethroids (biomarkers of internal dose). Markers of the biological effective dose were determined as hemoglobin adducts for diisocyanates and acrylamide, and as serum-albumin-adducts of aflatoxin B1 and diisocyanates. The analyses and quantitation of the protein adducts in blood or the metabolites in urine were mostly performed with LC-MS/MS or GC-MS in the presence of isotope-labeled internal standards. This review also addresses the critical aspects of the application, use and selection of biomarkers. For future biomonitoring studies, a more comprehensive approach is discussed to broaden the selection of compounds.

Exposure assessment of children living in homes with hookah smoking parents to polycyclic aromatic hydrocarbons: urinary level, exposure predictors, and risk assessment

Children are extremely liable to indoor air pollutants as their physiology and a few metabolic pathways are different from those of adults. The present cross-sectional study aimed to assess exposure of children living with parents who use hookah tobacco smoke to polycyclic aromatic hydrocarbons (PAHs) using a biomonitoring approach. The study was conducted on 25 children (7-13 years of age) exposed to hookah smoke at home and 25 unexposed age-matched children. Urinary levels of five metabolites of PAHs were quantified via headspace gas chromatography-mass spectrometry (GC-MS). Urinary malondialdehyde (MDA) was measured, as well. Information regarding the sociodemographic and lifestyle conditions was collected through interviews using managed questionnaires. The urinary 1-OH-NaP and 9-OH-Phe concentrations were respectively 1.7- and 4.6-folds higher in the case samples compared to the control group (p < 0.05). In addition, urinary MDA levels were 1.4 times higher in the exposed children than in the unexposed group, but the difference was not statistically significant (p > 0.05). Increasing the consumption of grilled and meat food in the diet increased the participants' urinary 2-OH-Flu and 1-OH-Pyr levels, respectively. Moreover, sleeping in the living room instead of the bedroom at night was a significant predictor of high 1-OH-NaP and 2-OH-NaP concentrations in the children's urine. Overall, the findings confirmed that children living in their homes with hookah-smoking parents were significantly exposed to naphthalene and phenanthrene. Hence, implementing protective measures is critical to reduce the exposure of this group of children.

Simultaneous quantification of pyrethroid metabolites in urine of non-toilet-trained children in Japan

Background

Pyrethroid (PYR) insecticides are widely used for controlling various pests. There are two types that differ in terms of usage: agricultural-purpose PYR (agriculture-PYR) and hygiene purpose PYR (hygiene-PYRs). Few studies exist on the exposure to these chemicals in small children. In this study, we conducted biomonitoring of urinary pyrethroid metabolites in 1.5-year-old children throughout the year.

Methods

Study subjects were 1075 children participating in an Aichi regional sub-cohort of the Japan Environment and Children’s Study as of 18-month health check-up. The concentrations of four specific hygiene-PYR metabolites including 2,3,5,6-tetrafluoro-1,4-benzenedimethanol (HOCH₂-FB-Al), and five common metabolites of hygiene- and agriculture-PYRs including 3-phenoxybenzoic acid (3PBA) and cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (DCCA), were measured in urine samples extracted from soiled diapers using a triple quadrupole gas chromatograph-mass spectrometer.

Results

The highest detection frequencies were for 3PBA, followed by DCCA, 1R-trans-chrysanthemum dicarboxylic acid, and HOCH₂-FB-Al. Among the six metabolites, urinary concentrations were seasonally varied. However, this variation was not observed in the most studied PYR metabolite, 3PBA. Spearman’s correlation analysis demonstrated a significant positive correlation between FB-Al and DCCA (r = 0.56) and HOCH₂-FB-Al and 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol (r = 0.60).

Conclusions

This biomonitoring survey found widespread and seasonally specific exposure to multiple hygiene- and agriculture-PYRs in 1.5-year-old Japanese children.

Exposure to benzene, toluene and polycyclic aromatic hydrocarbons in Nunavimmiut aged 16 years and over (Nunavik, Canada) - Qanuilirpitaa 2017 survey

There are numerous volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) that Inuit may be exposed to from combustion, cooking, heating, vehicle exhaust, active and passive smoking and other local sources of contaminants such as oil spills or open-air burning in landfills. To better assess the levels of exposure to these non-persistent chemicals, we measured a suite of benzene, toluene (two VOCs) and PAHs metabolites in pooled urine samples from youth and adults aged 16 years old and over who participated in the Qanuilirpitaa? 2017 Inuit Health Survey (Q2017), a population health survey conducted in Nunavik. A cost-effective pooling strategy was established and 30 different pools from individual urine samples (n = 1266) were created by grouping individual urine samples by sex, age groups and regions. To assess smoking and exposure to second-hand smoke, cotinine levels were measured in individual urine samples. We found that benzene, toluene, all detected PAHs metabolites and cotinine levels were significantly higher in Q2017 compared to adults in the Canadian Health Measure Survey Cycle 4 (2014-2015) or the general U.S population (2015-2016). Moreover, mean levels of one benzene metabolite, S-phenylmercapturic acid, and several PAHs metabolites, 1-naphthol, 2-and 3-hydroxyfluorene, and 4- and 9-hydroxyphenanthrene, known to be associated with smoking habits, were higher in Q2017 compared to reference values (RV₉₅) established for non-smokers in the general Canadian population. Furthermore, benzene and PAHs metabolites were all correlated with cotinine levels. Our results suggest that the high smoking prevalence in Nunavik is an important contributor to the elevated benzene and PAHs exposure. Other local sources may add to that exposure, although we were not able to account for their contribution. These data highlight the importance of regional and community efforts for reducing smoking and to encourage smoke-free homes in Nunavik, while continuing to investigate and reduce other possible local sources of exposure to benzene, toluene and PAHs.

Trends in environmental chemical concentrations in the Canadian population: Biomonitoring data from the Canadian Health Measures Survey 2007-2017

Ten years of nationally representative biomonitoring data collected between 2007 and 2017 are available from the Canadian Health Measures Survey (CHMS). These data establish baseline environmental chemical concentrations in the general population. Here we sought to evaluate temporal trends in environmental chemical exposures in the Canadian population by quantifying changes in biomarker concentrations measured in the first five two-year cycles of the CHMS. We identified 39 chemicals that were measured in blood or urine in at least three cycles and had detection rates over 50% in the Canadian population. We calculated geometric mean concentrations for each cycle using the survey weights provided. We then conducted analyses of variance to test for linear trends over all cycles. We also calculated the percent difference in geometric means between the first and most recent cycle measured. Of the 39 chemicals examined, we found statistically significant trends across cycles for 21 chemicals. Trends were decreasing for 19 chemicals from diverse chemical groups, including metals and trace elements, phenols and parabens, organophosphate pesticides, per- and polyfluoroalkyl substances, and plasticizers. Significant reductions in chemical concentrations included di-2-ethylhexyl phthalate (DEHP; 75% decrease), perfluorooctane sulfate (PFOS; 61% decrease), perfluorooctanoic acid (PFOA; 58% decrease), dimethylphosphate (DMP; 40% decrease), lead (33% decrease), and bisphenol A (BPA; 32% decrease). Trends were increasing for two pyrethroid pesticide metabolites, including a 110% increase between 2007 and 2017 for 3-phenoxybenzoic acid (3-PBA). No significant trends were observed for the remaining 18 chemicals that included arsenic, mercury, fluoride, acrylamide, volatile organic compounds, and polycyclic aromatic hydrocarbons. National biomonitoring data indicate that concentrations, and therefore exposures, have decreased for many priority chemicals in the Canadian population. Concentrations for other chemical groups have not changed or have increased, although average concentrations remain below thresholds of concern derived from human exposure guidance values. Continued collection of national biomonitoring data is necessary to monitor trends in exposures over time.

Development of a strategic approach for comprehensive detection of organophosphate pesticide metabolites in urine: Extrapolation of cadusafos and prothiofos metabolomics data of mice to humans

Objectives

The comprehensive detection of environmental chemicals in biospecimens, an indispensable task in exposome research, is advancing. This study aimed to develop an exposomic approach to identify urinary metabolites of organophosphate (OP) pesticides, specifically cadusafos and prothiofos metabolites, as an example chemical group, using an original metabolome dataset generated from animal experiments.

Methods

Urine samples from 73 university students were analyzed using liquid chromatography–high‐resolution mass spectrometry. The metabolome data, including the exact masses, retention time (t_R), and tandem mass spectra obtained from the human samples, were compared with the existing reference databases and with our original metabolome dataset for cadusafos and prothiofos, which was produced from mice to whom two doses of these OPs were orally administered.

Results

Using the existing databases, one chromatographic peak was annotated as 2,4‐dichlorophenol, which could be a prothiofos metabolite. Using our original dataset, one peak was annotated as a putative cadusafos metabolite and three peaks as putative prothiofos metabolites. Of these, all three peaks suggestive of prothiofos metabolites, 2,4‐dichlorophenol, 3,4,5‐trihydroxy‐6‐(2,4‐dichlorophenoxy) oxane‐2‐carboxylic acid, and (2,4‐dichlorophenyl) hydrogen sulfate were confirmed as authentic compounds by comparing their peak data with both the original dataset and peak data of the standard reagents. The putative cadusafos metabolite was identified as a level C compound (metabolite candidate with limited plausibility).

Conclusions

Our developed method successfully identified prothiofos metabolites that are usually not a target of biomonitoring studies. Our approach is extensively applicable to various environmental contaminants beyond OP pesticides.

Human biomonitoring reference values and characteristics of Phthalate exposure in the general population of Taiwan: Taiwan Environmental Survey for Toxicants 2013-2016

Since a 2011 incident involving phthalate-tainted food, Taiwanese people have become concerned with food quality, and they are still being exposed to certain levels of phthalates. However, no nationwide human biomonitoring survey had been conducted to gather information on levels or reference values (RVs) of phthalates in the Taiwanese population. We aimed to establish the urinary levels and RVs of phthalate metabolites and identify exposure characteristics among Taiwan's population. We enrolled 1857 participants 7 years of age and older from the Taiwan Environmental Survey for Toxicants (TESTs) conducted during 2013-2016. Levels of 11 phthalate metabolites in each participant's urine samples were determined using liquid chromatography-tandem mass spectrometry. For all phthalate metabolites except for mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP), and mono-ethylhexyl phthalate (MEHP), urinary median levels were significantly higher in the 7-17-year old group than in the ≧18-year-old group. For most phthalate metabolites and in the general population, the geometric mean decreased with increasing age. Median levels of MEP (19.55 μg/L), mono-benzyl phthalate (MBzP) (2.11 μg/L), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) (22.82 μg/L), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEOHP) (16.08 μg/L), ΣDibutyl phthalate metabolites (ΣDBPm) (0.17 nmol/mL), Σdi-(2-ethylhexyl) phthalate metabolites (ΣDEHPm) (0.29 nmol/mL) were higher in participants from central Taiwan than those from other areas. The median level of DBP (ΣDBPm: 0.20 nmol/mL) was significantly higher in participants from harbor areas than those from other urbanization groups. The RV of the 95 percentile (P₉₅) for phthalate metabolites in the 7-17/≧18-year-old groups were 185.95/208.19 μg/L for MMP, 198.46/265.81 μg/L for MEP, 119.85/69.99 μg/L for mono-isononyl phthalate (MiBP), 165.19/204.32 μg/L for Mono-n-butyl phthalate (MnBP), 15.61/11.73 μg/L for MBzP, 62.09/59.23 μg/L for MEHP, 149.70/69.66 μg/L for MEHHP, 112.06/35.07 μg/L for MEOHP, 195.20/93.83 μg/L for mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), 45.66/27.69 μg/L for mono-(2-carboxymethylhexyl) phthalate (MCMHP), and 9.09/12.13 μg/L for mono-iso-nonyl phthalate (MiNP). We concluded that phthalate exposure of the general population in Taiwan varies by sex, age, region, and urbanization level. Exposure by the 7-17-year-old group to DMP, DBP, and DEHP in Taiwan remains higher than that of youth from other countries. RV of phthalate metabolites in Taiwan were established in the current study.

Analytical challenges in human exposome analysis with focus on environmental analysis combined with metabolomics

Environmental factors, such as chemical exposures, are likely to play a crucial role in the development of several human chronic diseases. However, how the specific exposures contribute to the onset and progress of various diseases is still poorly understood. In part, this is because comprehensive characterization of the chemical exposome is a highly challenging task, both due to its complex dynamic nature as well as due to the analytical challenges. Herein, the analytical challenges in the field of exposome research are reviewed, with specific emphasis on the sampling, sample preparation, and analysis, as well as challenges in the compound identification. The primary focus is on the human chemical exposome, that is, exposures to mixtures of environmental chemicals and its impact on human metabolome. In order to highlight the recent progress in the exposome research in relation to human health and disease, selected examples of human exposome studies are presented.

Non-linear model analysis of the relationship between cholinesterase activity in rats exposed to 2, 2-dichlorovinyl dimethylphosphate (dichlorvos) and its metabolite concentrations in urine

Urinary dialkylphosphates (DAPs) are measured to assess exposure to organophosphorus pesticides (OPs), but they are common metabolites of OPs and not specific indices for individual agents. Biomonitoring (BM) of urinary DAPs has been widely adopted as an assessment of individual exposure in general environments, however, guidance values for DAPs based on health effects have yet to be established. The present study aimed to clarify the relationship between the amount of urinary dimethylphosphate (DMP), a metabolite of dichlorvos (DDVP), and the inhibition of cholinesterase (ChE) activity in rats exposed to DDVP. The relationship was analyzed using a nonlinear model analysis, and the excretion level of urinary DMP equivalent to ChE 20 % inhibition (EL20) and the lower limit of the 95 % confidence interval of EL20 (ELL20) were estimated. EL20 and ELL20 (mg/24 h urine) of brain, erythrocyte, and plasma ChE activities after 10-day administration of DDVP were 0.21 and 0.15, 0.11 and 0.06, and 0.23 and 0.09, respectively. Extrapolating ELL20 of the brain ChE to humans, the range of 24 h urinary DMP concentration according to the 20 % inhibition of cholinesterase activity was estimated to be 20.5-30.8 mg/l. In conclusion, the amount of urinary DMP as ELL20 for DDVP exposure was identified and could probably be used as a novel index for the assessment of risk from OP exposure. Further studies are needed to clarify the ELL20 s derived from OPs other than DDVP, for informing efforts to establish guidance values of urinary OP metabolites that should prevent neurotoxicity.

Benzene metabolite SPMA and acrylamide metabolites AAMA and GAMA in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V)

Benzene and acrylamide are carcinogenic substances contained inter alia in tobacco smoke. The mercapturic acid metabolites of benzene, N-acetyl-S-phenyl-L-cysteine (SPMA), and of acrylamide, N-acetyl-S-(3-amino-3-oxopropyl)-cysteine (AAMA) and N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)-cysteine (GAMA), were analysed in 2260 first-morning void urine samples from children and adolescents aged 3-17 years, participating in the population-representative German Environmental Survey on Children and Adolescents, GerES V 2014-2017. SPMA was detected in 98% of the participants with a geometric mean (GM) of 0.097 μg/L urine. Smokers had about 10-fold higher levels of the benzene metabolite SPMA than non-smokers. The sample comprises of 48 self-reported smokers, mainly in the oldest age group (14-17-year-olds). Second-hand smoke exposure, living near busy or very busy roads, and using domestic fuels for heating were additionally associated with higher benzene metabolite levels. SPMA levels in GerES V were lower compared to levels found in other countries, which in part however may reflect different proportions of smokers. The acrylamide metabolites AAMA and GAMA were detected in 100% of the participants with a GM of 72.6 μg/L urine for AAMA and 15.0 μg/L urine for GAMA. Smoking children and adolescents had about 2.5-fold higher AAMA levels than non-smoking ones. The frequency of consumption of french-fried potatoes and potato crisps consumption was also positively associated with urinary AAMA and GAMA levels. Compared to the urinary AAMA and GAMA levels in Germany and other countries, levels in GerES V tended to be higher than in the few studies reported. The urinary levels of the benzene biomarker SPMA, and the acrylamide biomarkers AAMA and GAMA build the basis to derive reference values for the exposure of children and adolescents in Germany. The results reveal options for exposure reduction mainly in personal choices regarding smoking and diet, but also requiring policy to maintain efforts in non-smoking regulations and improving ambient air quality. Providing these results also to the European HBM Initiative HBM4EU will contribute to gain knowledge on the exposure of the European population, the health impact of carcinogens and thus providing support for substantiated exposure assessment.

Pooled analysis of genotoxicity markers in relation to exposure in the Flemish Environment and Health Studies (FLEHS) between 1999 and 2018

BACKGROUND

The Flemish Environment and Health Studies (FLEHS) are human biomonitoring surveys running in Flanders since 1999. Additionally to biomarkers of exposure, markers of genotoxicity and oxidative stress have been measured, including the alkaline comet and micronucleus assay in peripheral whole blood cells, and urinary concentrations of 8-oxo-2'-deoxyguanosine (8-oxodG).

AIM

Exposure-effect associations were explored in a pooled dataset of nine different cross-sectional FLEHS surveys. Data of adolescents collected in a time frame of about 20 years (1999-2018) were compiled. The aim of the study was to examine whether increased variation in exposure, lifestyle and environmental factors would lead to more powerful and robust exposure-effect associations.

MATERIALS & METHODS

The biomarkers were measured in 2283 adolescents in the age range of 14-18 years. Exposure to polycyclic aromatic hydrocarbons [1-hydroxypyrene (1-OHP)], benzene (tt'-muconic acid), metals (arsenic, cadmium, copper, nickel, thallium, lead, chromium), persistent organochlorines and phthalates were assessed in blood or urine. Furthermore, outdoor air levels of particulate matter (PM₁₀ and PM_2.5) at the residences of the youngsters were calculated. Pooled statistical analysis was done using mixed models. Study-specific differences in the genotoxicity markers and in the strength/direction of the association were accounted for. This was done by incorporating the random factor 'study' and a random study slope (if possible). The exposure markers were centered around the study-specific mean in order to correct for protocol changes over time.

RESULTS

A significant association was observed for the urinary oxidative stress marker 8-oxodG, which was positively associated with 1-OHP (5% increase for doubling of 1-OHP levels, p = 0.001), and with urinary copper (26% increase for doubling of copper levels, p = 0.001), a metal involved in the Fenton reaction in biological systems. 8-oxodG was also associated with the sum of the metabolites of the phthalate di(2-ethylhexyl) phthalate (DEHP) (3% increase for doubling of the DEHP levels, p = 0.02). For those associations, data pooling increased the statistical power. However, some of the associations in the individual surveys, were not confirmed in the pooled analysis (such as comet assay and 8-oxodG vs. atmospheric PM; and 8-oxodG vs. urinary nickel). This may be due to inconsistencies in exposure-effect relations and/or variations in the pollutant mix over time and regions.

CONCLUSION

Pooled analysis including a large population of 2283 Flemish adolescents showed that 8-oxodG, a marker of oxidative DNA damage is a valuable marker to assess impact of daily life pollutants, such as PAHs, Cu and the phthalate DEHP.

Perceptions and Attitudes of Gynecologic and Pediatric Professionals Regarding Dietary Exposure to Chemical Pollutants

There is increasing concern regarding the potential implications of continuous dietary exposure to low doses of artificial chemical pollutants, particularly in critical life stages such as pregnancy and lactation. Within a wider social research, we analyzed the risk perception, discourses, and attitudes of health professionals regarding dietary exposure to artificial chemical contaminants. Data was collected by personal interviews on 35 health professionals from two Spanish regions. Although the participants' discourses were strongly dominated by the nutritional composition and microbiological contamination, 34 expressed some concern regarding metals, and 23 regarding pesticides. Although only one participant mentioned a plasticizer (i.e., bisphenol A), we noted an underlying concern, since six professionals admitted to recommending pregnant women to somewhat avoid plastic food containers, and were aware of mother-to-child transmission and accumulation of artificial chemicals. The ubiquity of the exposure, the inability to locate the threat, and contradictory messages can all create a sense of helplessness and subsequent cognitive adjustments. Our participants also reported a lack of information, particularly on emerging pollutants. In conclusion, we found a range of valuable discourses that can aid in orienting public health strategies aimed at health professionals who have a substantial influence on their patients.

Biomonitoring of Bis(2-ethylhexyl)phthalate (DEHP) in Italian children and adolescents: Data from LIFE PERSUADED project

The Bis(2-ethylhexyl)phthalate (DEHP), a widespread plasticizer, is considered an endocrine disrupting chemical with main toxicological effects on reproductive and metabolic systems. Human biomonitoring (HBM) studies are promoted to evaluate the background exposure levels. In the frame of LIFE PERSUADED project, the HBM study measured DEHP main metabolites (mono-(2-ethylhexyl) phthalate, MEHP; 2-ethyl-5-hydroxy-hexylphthalate, MEHHP; 2-ethyl-5-oxo-hexylphthalate, MEOHP) in Italian children and adolescent (4-14 years old) according to geographical macro-areas and areas, age and sex. Children from the South and the Centre of Italy showed higher median levels of DEHP, as a sum of its metabolites (48.14 and 47.80 μg/L), than those from the North (39.47 μg/L; p = 0.0090 and 0.0004, respectively). Considering the total population, boys are more exposed than girls (only as urinary volume), and children aged 4-6 years have higher median levels than those 7-10 and 11-14 years old. The derived reference values (RV95) for DEHP in children is 168 μg/L. The relative metabolic rates of DEHP, the background levels and, thus, the RV95, vary with the geographical area, age and sex, indicating that all these parameters should be considered in the risk assessment.

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.

Embryotoxicity assessment and efficient removal of naphthalene from water by irradiated graphene aerogels

Naphthalene has remained a challenge how to eradicate it from the water because of its carcinogenic risk to humans. In the present study, naphthalene prominently increased the rates of embryonic mortality and malformation, and decreased the hatchability of zebrafish which have a high developmental similarity to humans. Moreover, multiple-organ toxicity were notably found in naphthalene-treated zebrafish. Here, irradiated graphene aerogel (IGA) was successfully prepared from high-energy electron beam to generate more wrinkles, folds, defects and a strong absorption capability for naphthalene, compared with the non-irradiated graphene aerogel. IGA was outstandingly found to remove naphthalene from the embryo culture medium, and subsequently inhibit the embryotoxicity and maintain tissue integrity by restoring cardiac function, attenuating apoptosis signals, recovering eye morphology and structure, reducing expression of heat shock protein 70 in the tissues and promoting behavioral capacity. Meanwhile, no obvious negative impact of IGA was found in the developing zebrafish from embryo to larvae. Consequently, reduction in the toxicity of naphthalene during zebrafish embryogenesis was mediated by IGA as an advanced strategy.

Biomonitoring of the adult population in the area of turin waste incinerator: Baseline levels of polycyclic aromatic hydrocarbon metabolites

Exposure to polycyclic aromatic hydrocarbons (PAHs) was assessed in a cohort of 394 subjects, 198 residing in three small municipalities near a new waste-to-energy (WTE) incinerator located in the Turin area, and 196 residing in neighbouring control areas in the town (of Turin). The assessment of exposure to PAHs was part of a human biomonitoring study aimed at assessing potential incremental exposure to pollutants related to incineration activities through the analysis of such pollutants before the plant start-up, and after one and three years of operation. The exposure assessment described in this study was carried out before the start-up of the WTE incinerator. Ten monohydroxy-PAHs (OH-PAHs) were analyzed in urine samples, consisting in the principal metabolites of naphthalene (NAP), fluorene (FLU), phenanthrene (PHE), and pyrene (PYR). Concentrations of the sum of OH-PAHs (Σ₁₀OH-PAHs) were in the range of 525-85200 ng/g creatinine, with P₅₀ equal to 6770 ng/g creatinine. Metabolites of naphthalene were found at the highest concentrations (P₅₀ values of 892 and 4300 ng/g creatinine for 1- and 2-OH-NAP, respectively) followed by the three OH-FLUs (P₅₀ values of individual compounds in the range of 58.2-491 ng/g creatinine), the four OH-PHEs (P₅₀ values in the range of 30.5-145 ng/g creatinine), and 1-OH-PYR (P₅₀ value of 82.8 ng/g creatinine). Concentrations of 1-OH-NAP, 9-OH-FLU, 1-, 2-, 3, 4-OH-PHE, and 1-OH-PYR were significantly lower in subjects living near the WTE plant compared to those living in the town of Turin, with differences between the two groups in the range 14-31%. Smoking habits markedly influence the urinary concentrations OH-PAHs. Median concentrations of the single metabolites in smokers were from 1.4 fold (for 4-OH-PHE) to 14 fold higher (for 3-OH-FLU) than those observed in non-smokers. The heating system used also resulted to be a major contributor to PAH exposure. Concentrations of OH-PAHs were generally comparable with those observed in other industrialized countries. The profile pattern was consistent with those reported in the literature. Concentrations of OH-PAHs assessed in this study may be considered indicative of the background exposure to PAHs for adult population living in an urban and industrialized area.

Exposure levels of organophosphate pesticides in Japanese diapered children: Contributions of exposure-related behaviors and mothers' considerations of food selection and preparation

Organophosphate (OP) pesticide exposure is a public health issue due to its potential link to neurodevelopmental problems in children. This study aimed to examine the exposure levels of OP pesticides in Japanese toddlers and explore the possible contributions of their exposure-related behaviors and their mothers' considerations of food selection and preparation to their exposure levels to OP pesticides. We recruited diapered children participating in the Japan Environment and Children's Study and collected used disposable diapers from 1037 children between June 2015 and August 2016. Six dialkylphosphates (DAPs) were measured in the urine extracted from the diapers. The geometric means of urinary creatinine (Cr)-unadjusted and Cr-adjusted concentrations of the sum of the six DAPs (ΣDAP) were 120 nmol/L and 243 nmol/g Cr, respectively. A receiver operating characteristic curve analysis for propensity scores of exposure-related factors revealed that discriminatory powers determining whether Cr-unadjusted and Cr-adjusted ΣDAP concentrations exceeded the 95th percentile values were lower for the exposure-related behaviors (areas under the curve, 0.72 and 0.69, respectively) and the mothers' considerations of food selection and preparation (0.55 and 0.57, respectively) than those for the foodstuffs ingested on the survey day (0.75 and 0.81, respectively). Some exposure-related behaviors, namely the use of insecticides, herbicides, and insect repellent sprays, were found to be associated with increased Cr-unadjusted ΣDAP concentrations (odds ratio, 2.0-2.6) via multivariate analysis. In contrast, only the use of a fragrance or deodorant was associated with increased Cr-adjusted ΣDAP concentrations (odds ratio, 2.3). This is the first report on the exposure levels of OP pesticides in a large number of Japanese toddlers. Some household chemical product use was related to OP common metabolite DAP levels. Japanese toddlers were widely exposed to OP pesticide.

Anthropometric measures at age 3 years in associations with prenatal and postnatal exposures to chlorophenols

BACKGROUND

Chlorophenols (CPs), suspected as endocrine disrupting chemicals, exposure during early life may contribute to body size. However, limited human data with inconsistent findings have examined the developmental effects of CPs exposure.

OBJECTIVE

To explore associations between prenatal and postnatal CPs exposure and anthropometric parameters in children aged 3 years.

METHODS

A subset of 377 mother-child pairs with urinary five CP concentrations were enrolled from a prospective birth cohort. Generalized linear models were conducted to evaluate associations of CPs exposure with children's anthropometric measures.

RESULTS

Maternal urinary 2,4,6-trichlorophenol (2,4,6-TCP) concentrations were significantly negatively associated with weight z scores [regression coefficient (β) = -0.51, 95% confidence interval (CI): -0.96, -0.05; p = 0.01], weight for height z scores (β = -0.54, 95% CI: -1.02, -0.06; p = 0.01) and body mass index (BMI) z scores (β = -0.53, 95% CI: -1.03, -0.03; p = 0.01) of children aged 3 years, after adjustment for potential confounders and postnatal CPs exposure. In the sex-stratified analyses, these inverse associations remained among boys, while in girls, positive associations of prenatal 2,4,6-TCP exposure with weight for height z scores and BMI z scores were observed. Postnatal exposure to 2,5-diclorophenol (2,5-DCP) was positively associated with weight z scores (β = 0.26, 95% CI: 0.02, 0.50; p = 0.04), after controlling for possible confounders and maternal CPs exposure during pregnancy. Considering potential sex-specific effects, these associations were only observed in girls.

CONCLUSIONS

Our findings indicate that prenatal 2,4,6-TCP exposure and postnatal 2,5-DCP exposure may have adverse and sex-specific effects on children's physical development.

Study Design, Rationale and Procedures for Human Biomonitoring of Hazardous Chemicals from Foods and Cooking in Korea

Objectives: A nationwide biomonitoring program identified the long-term trends of environmental exposures to hazardous chemicals in the general population and found geographical locations where body burdens of an exposed group significantly differed from those of the general population. The purpose of this study is to analyze the hazardous compounds associated with foods and cooking in the nationwide general population for evaluation of the environmental exposures and health risk factors and for the establishment of the reference levels at the national level. Methods: During 2009–2010, the National Institute of Food and Drug Safety Evaluation (NIFDS) conducted a nationwide human biomonitoring study, including a questionnaire survey and environmental exposure assessments for specific hazardous compounds from foods and cooking among the general population in South Korea. Results: A total of 2139 individuals voluntarily participated in 98 survey units in South Korea, including 889 (41.6%) men and 1250 women (58.4%). Bio-specimens (serum and urine) and questionnaires were collected from the study population. Acrylamides, heterocyclic amines (HCAs), phenols, and phthalates were analyzed from urine, and perfluorinated compounds (PFCs) and organic chloride pesticides (OCPs) were analyzed from serum samples. The information on exposure pathway and geographical locations for all participants was collected by questionnaire interviews, which included demographic characteristics, socioeconomic status, history of family diseases, conditions of the indoor and outdoor environment, lifestyles, occupational history, and food and dietary information. Conclusion: We describe the design of the study and sampling of human biospecimen procedures including bio-sample repository systems. The resources produced from this nationwide human biomonitoring study and survey will be valuable for use in future biomarkers studies and for the assessment of exposure to hazardous compounds associated with foods and cooking.

The extent and predictors of phthalate exposure among couples undergoing in vitro fertilization treatment

Phthalates are chemicals used as plasticizers and solvents in many consumer products but are suspected of disrupting the endocrine system and are known for their reproductive/developmental health risks. This study examined the extent and predictors of phthalate exposure among 599 couples undergoing in vitro fertilization. A questionnaire was administered to obtain sociodemographic, health, and lifestyle data, and two spot urine samples were collected from the couples to analyze eight phthalate metabolites, cotinine (COT) as a smoking index, and creatinine to adjust for urine dilution. Seven phthalate metabolites were detected in > 94% of the urine samples, and monobenzyl phthalate (MBzP) was found in 24% of the women and 26% of their male partners. Median phthalate levels were highest for monoethyl phthalate (MEP), at 333.26 μg/l in women and 290 μg/l in male partners, and lowest for MBzP, at 1.17 μg/l in women and 1.14 μg/l in male partners. Correlation coefficients of ≥ 0.4 between the women and their male partners for the eight urinary phthalate metabolites may indicate a shared source of exposure. A multivariate regression model was used to assess the association between predictors and each urinary phthalate metabolite. Several potential predictors for the variations in specific urinary phthalate metabolites were identified, including the body mass index, age, socioeconomic status, and regional distribution for both women and their male partners but with slightly different patterns. Women with a history of breastfeeding, using bottled water for cooking and storing food in plastic bags had lower MEP (8.7%), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) (9.2%), and both mono-iso-butyl phthalate and MECPP (8.2 and 8.1%). A history of contraceptive use was associated with an increase in MECPP (8.7%), mono-(2-ethyl-5-hydroxyhexyl) phthalate (11.4%), mono-(2-ethyl-5-oxohexyl) phthalate (7.6%), and the molar sum of bis (2-ethylhexyl) phthalate metabolites (8.9%). Urinary COT levels were associated with an increase of 10-16% in all urinary metabolites in women but of only 10.5% in mono-(2-ethylhexyl) phthalate in male partners. More than 95% of the couples reported the use of cosmetics, perfumes, and personal-care products, but we were not able to find associations with urinary phthalate metabolites, perhaps due to their short half-lives. MEP levels associated with the use of household cleaning products were 11.2% higher in male partners. Our levels were generally higher than those reported elsewhere, perhaps due to different lifestyles, cultural practices, dietary habits, use of personal-care products, and governmental legislation.

Leveraging the Canadian Health Measures Survey for environmental health research

Since 2007, the nationally representative, cross-sectional Canadian Health Measures Survey (CHMS) has collected detailed health and exposure data from more than 25,000 Canadians, including a wide range of chemical biomarkers analyzed in blood, urine, and environmental media. This article highlights the extent to which the CHMS dataset has been used in the peer-reviewed environmental health literature and opportunities for further expanding usage of the dataset. A literature search (2007-2018) was performed to identify peer-reviewed studies that have made substantive use of the CHMS dataset. Studies were analyzed according to the study type, data usage, populations studied, environmental health themes, citation/publication data, and institutional collaborations. A total of 51 environmental-health related CHMS studies were identified, including studies related to indoor and outdoor air quality, the built environment, and chemical and environmental tobacco smoke exposures. Health indicator data are being increasingly exploited, as is the ability to combine cycle datasets over time. Although these studies covered a range of environmental exposures, many CHMS variables remain underutilized. The CHMS dataset provides a valuable portrait of chemical exposures in Canadians of all ages, linked to a wide variety of health indicators. Many opportunities remain to exploit and expand both the use of the dataset and collaborations between Canadian agencies and domestic and international research institutions.

Human biomonitoring reference values: Differences and similarities between approaches for identifying unusually high exposure of pollutants in humans

In exposure and risk assessment, the indication of unusually high exposure levels in humans to chemicals has been considered as an important objective for decades. To realize this objective, reference values (RV) need to be derived. However, while there is a tendency towards using the 95th percentile as a basis for deriving these reference values there is still no consensus. Moreover, side approaches have evolved including deriving RVs based on other percentiles, reporting multiple RVs or only reporting percentiles. The purpose of this article is to give an overview of the current literature, to point out differences and similarities between existing approaches, and to highlight important criteria for the derivation of RVs. We observe the majority of studies to base RVs on the 95th percentile and its 95% confidence interval which can been justified by statistical paradigms, present arguments for a single defined reference value, and discuss characteristics which call for more consistency. To conclude, our overview provides a first step towards a more homogenous and standardized derivation procedure to identify unusually high exposures in exposure science.

Austrian reference values for phthalate metabolite exposure in children/adolescents and adults

Reference values (RV₉₅) are statistically derived values comprising the rounded 95th percentiles within the 95% confidence interval and indicate the upper margin of background exposure to chemical substances in a population at a given time period. Based on representative national human biomonitoring data on several urinary phthalate metabolites in children, adolescents and adults from 2010 to 2011, RV₉₅ were derived for the Austrian population based on a IUPAC guideline and the recommendation of the German Human Biomonitoring Commission. The RV₉₅ (rounded values) for phthalate metabolites in children and adolescents aged 6-15 years are 110 μg/l (confidence interval of 95th population percentile: 83.7-163) for mono-ethyl phthalate (MEP), 45 μg/l (40.9-60.6) for mono-n-butyl phthalate (MnBP), 130 μg/l (126-161) for mono-isobutyl phthalate (MiBP), 25 μg/l (17.8-33.6) for mono-benzyl phthalate (MBzP), 100 μg/l (94.0-126) for the sum of the di(2-ethylhexyl) phthalate (DEHP) metabolites including mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP), mono(2-ethyl-5-oxohexyl) phthalate (5oxo-MEHP) and mono(2-ethyl-5-carboxypentyl) phthalate (5cx-MEPP), and 1.5 μg/l (0.64-1.6) for mono-cyclohexyl phthalate (MCHP). In adults aged 18-81 years, RV₉₅ are 440 μg/l (353-636) for MEP, 40 μg/l (33.1-52.1) for MnBP, 110 μg/l (87.3-118) for MiBP, 10 μg/l (7.2-11.8) for MBzP, 50 μg/l (44.6-68.3) for the sum of MEHP, 5OH-MEHP, 5oxo-MEHP and 5cx-MEPP, and 1.5 μg/l (0.95-1.8) for MCHP. For almost all investigated metabolites, children and adolescents exhibit higher RV₉₅ than adults, with the exceptions being MEP and MCHP. Compared to available RV₉₅ for Germany and Canada, Austrian values are lower for all investigated population groups.