The production and use of the plasticisers Hexamoll® DINCH (di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate) and DPHP (di-(2-propylheptyl) phthalate) have increased after both chemicals were introduced ...into the market in the early 2000s as substitutes for restricted high molecular weight phthalates.
During the population representative German Environmental Survey (GerES) of Children and Adolescents (GerES V, 2014–2017), we collected urine samples and measured the concentrations of DINCH and DPHP metabolites in 2228 and in a subsample of 516 participants, respectively.
We detected DINCH and DPHP metabolites in 100% and 62% of the 3–17 years old children and adolescents, respectively.
Geometric means of DINCH metabolites were 2.27 μg/L for OH-MINCH, 0.93 μg/L for oxo-MINCH, 1.14 μg/L for cx-MINCH and 3.47 μg/L for DINCH (Σ of OH-MINCH + cx-MINCH). Geometric means of DPHP metabolites were 0.30 μg/L for OH-MPHP, 0.32 µg/L for oxo-MPHP and 0.64 μg/L for DPHP (Σ of OH-MPHP + oxo-MPHP). The 3–5 years old children had almost 3-fold higher DINCH biomarkers levels than adolescents (14–17 years). Higher concentrations of DPHP biomarkers among young children only became apparent after creatinine adjustment. Urinary levels of DINCH but not of DPHP biomarkers were associated with the levels of the respective plasticisers in house dust.
When compared to HBM health-based guidance values, we observed no exceedance of the HBM-I value of 1 mg/L for DPHP (Σ of OH-MPHP + oxo-MPHP). However, 0.04% of the children exceeded the health based guidance value HBM-I of 3 mg/L for DINCH (Σ of OH-MINCH + cx-MINCH). This finding shows that even a less toxic replacement of restricted chemicals can reach exposures in some individuals, at which, according to current knowledge, health impacts cannot be excluded with sufficient certainty.
In conclusion, we provide representative data on DINCH and DPHP exposure of children and adolescents in Germany. Further surveillance is warranted to assess the substitution process of plasticisers, and to advise exposure reduction measures, especially for highly exposed children and adolescents. Providing the results to the European HBM Initiative HBM4EU will support risk assessment and risk management not only in Germany but also in Europe.
Phthalates are a group of widely used chemicals and humans are exposed to them in their daily life. Some phthalates may affect the hormonal balance in both children and adults. The aim of this study ...was to assess the phthalate exposure and its determinants among children at age of 7 years from the Polish Mother and Child Cohort Study (REPRO_PL). 250 urine samples collected in 2014–2015 were analysed for 21 metabolites of 11 parent phthalates using on-line high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). This represents the most extensive set of phthalate metabolites ever determined for Poland. Ten metabolites were quantifiable in 100% of the samples, another eight in >90%. The highest median concentrations were found for the primary monoester metabolites of di-iso-butyl (MiBP, 72.4 μg/l), di-n-butyl (MnBP, 56.3 μg/l) and diethyl (MEP, 42.0 μg/l) phthalate, followed by the sum of di-2-ethylhexyl (ΣDEHP, 89.3 μg/l) and di-iso-nonyl (ΣDiNP, 21.9 μg/l) phthalate metabolites. Metabolite concentrations were higher in children at 7 years than in the same children at age 2 or in their mothers during pregnancy. Generally, phthalate exposures in this study were much higher than exposures reported in other European populations. Multivariate regression models showed that body mass index, place of residence, breastfeeding duration, socio-economic status and parental education were associated with the metabolite levels in the 7-year old children. Daily intake and hazard index calculations revealed that a small percentage of children (around 3–10%) exceeded the tolerable daily intakes established by international institutions such as EFSA and U.S. EPA indicating that these children might be at risk of anti-androgenic effects from the individual and cumulative exposure to phthalates. Thus, further monitoring of this population, by educational programs and follow-up interventions, is required.
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•Phthalate exposures in children from Poland ranked among the highest.•The most prevalent phthalate metabolites were MEP, MiBP, MnBP, ΣDEHP and ΣDiNP.•BMI, place of residence and breastfeeding are associated with phthalate body burdens.•Exposures in the upper percentiles exceeded levels that cannot be regarded as safe.
Human health risk assessment is historically built upon animal testing, often following Organisation for Economic Co-operation and Development (OECD) test guidelines and exposure assessments. Using ...combinations of human relevant in vitro models, chemical analysis and computational (in silico) approaches bring advantages compared to animal studies. These include a greater focus on the human species and on molecular mechanisms and kinetics, identification of Adverse Outcome Pathways and downstream Key Events as well as the possibility of addressing susceptible populations and additional endpoints. Much of the advancement and progress made in the Next Generation Risk Assessment (NGRA) have been primarily focused on new approach methodologies (NAMs) and physiologically based kinetic (PBK) modelling without incorporating human biomonitoring (HBM). The integration of toxicokinetics (TK) and PBK modelling is an essential component of NGRA. PBK models are essential for describing in quantitative terms the TK processes with a focus on the effective dose at the expected target site. Furthermore, the need for PBK models is amplified by the increasing scientific and regulatory interest in aggregate and cumulative exposure as well as interactions of chemicals in mixtures. Since incorporating HBM data strengthens approaches and reduces uncertainties in risk assessment, here we elaborate on the integrated use of TK, PBK modelling and HBM in chemical risk assessment highlighting opportunities as well as challenges and limitations. Examples are provided where HBM and TK/PBK modelling can be used in both exposure assessment and hazard characterization shifting from external exposure and animal dose/response assays to animal-free, internal exposure-based NGRA.
Parabens are used as preservatives in personal care and consumer products, food and pharmaceuticals. Their use is controversial because of possible endocrine disrupting properties. In this study, we ...investigated metabolism and urinary excretion of methyl paraben (MeP),
iso
-butyl paraben (
iso
-BuP) and
n
-butyl paraben (
n
-BuP) after oral dosage of deuterium-labeled analogs (10 mg). Each volunteer received one dosage per investigated paraben separately and at least 2 weeks apart. Consecutive urine samples were collected over 48 h. In addition to the parent parabens (free and conjugated) which are already used as biomarkers of internal exposure and the known but non-specific metabolites,
p
-hydroxybenzoic acid (PHBA) and
p
-hydroxyhippuric acid (PHHA), we identified new, oxidized metabolites with hydroxy groups on the alkyl side chain (3OH-
n
-BuP and 2OH-
iso
-BuP) and species with oxidative modifications on the aromatic ring. MeP represented 17.4 % of the dose excreted in urine, while
iso
-BuP represented only 6.8 % and
n
-BuP 5.6 %. Additionally, for
iso
-BuP, about 16 % was excreted as 2OH-
iso
-BuP and for
n
-BuP about 6 % as 3OH-
n
-BuP. Less than 1 % was excreted as ring-hydroxylated metabolites. In all cases, PHHA was identified as the major but non-specific metabolite (57.2–63.8 %). PHBA represented 3.0–7.2 %. For all parabens, the majority of the oral dose captured by the above metabolites was excreted in the first 24 h (80.5–85.3 %). Complementary to the parent parabens excreted in urine, alkyl-chain-oxidized metabolites of the butyl parabens are introduced as valuable and contamination-free biomarkers of exposure.
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•Ubiquitous nonylphenol (NP) exposure in 7-year-old Japanese children (n = 180).•Specific urinary biomarkers OH-NP and oxo-NP detected in 100% and 66% of samples.•Median and maximum ...daily NP intakes at 0.14 and 0.95 µg/(kg bw*d).•Associations of OH-NP and oxidative stress biomarkers HEL and HNE.•Only slight annual decrease in NP exposure of 4.7% between 2012 and 2017.
Nonylphenol (NP) has been under scrutiny for decades due to its endocrine-disrupting properties and its ubiquity in the environment. Despite its widespread occurrence, robust and reliable exposure data are rare. In this study, we used human biomonitoring (HBM) measuring the novel urinary alkyl-chain-oxidized biomarkers OH-NP and oxo-NP to determine NP exposure in 7-year-old Japanese children. The new biomarkers are advantageous over measuring unchanged NP because they are not prone to external contamination. We analyzed 180 first morning void urine samples collected between 2012 and 2017. OH-NP and oxo-NP were detected in 100% and 66% of samples at median concentrations of 2.69 and 0.36 µg/L, respectively. 10-fold concentration differences between OH-NP and oxo-NP are in line with recent findings on human NP metabolism. Based on OH-NP we back-calculated median and maximum NP daily intakes (DI) of 0.14 and 0.95 µg/(kg bw*d). These DIs are rather close to but still below the current provisional tolerable daily intake of 5 µg/(kg bw*d) by the Danish Environmental Protection Agency. Between 2012 and 2017 the DIs decreased by an average of 4.7% per year. We observed no seasonal changes or gender differences and questionnaire data on food consumption, housing characteristics or pesticide use showed no clear associations with NP exposure. Urinary OH-NP was weakly associated with the oxidative stress (lipid peroxidation) biomarkers N-ε-hexanoyl-lysine (HEL) and trans-4-hydroxy-2-nonenal (HNE) (Spearman ρ = 0.30 and 0.22, respectively), but not with 8-hydroxy-2′-deoxyguanosine (8-OHdG). Further research is needed to identify and understand the major sources of NP exposure and to investigate a potential role in oxidative stress. This study is the first to investigate NP exposure in Japanese children based on robust and sensitive HBM data. It is a first step to fill the long-standing gap in quantitative human NP exposure monitoring and risk assessment.
The German Environmental Specimen Bank (ESB) continuously collects 24-h urine samples since the early 1980s in Germany. In this study we analyzed 300 urine samples from the years 2007 to 2015 for 21 ...phthalate metabolites (representing exposure to 11 parent phthalates) and combined the data with two previous retrospective measurement campaigns (1988 to 2003 and 2002 to 2008). The combined dataset comprised 1162 24-h urine samples spanning the years 1988 to 2015. With this detailed set of human biomonitoring data we describe the time course of phthalate exposure in Germany over a time frame of 27 years. For the metabolites of the endocrine disrupting phthalates di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP) and butylbenzyl phthalate (BBzP) we observed a roughly ten-fold decline in median metabolite levels from their peak levels in the late 1980s/early 1990s compared to most recent levels from 2015. Probably, bans (first enacted in 1999) and classifications/labelings (enacted in 2001 and 2004) in the European Union lead to this drop. A decline in di-isobutyl phthalate (DiBP) metabolite levels set in only quite recently, possibly due to its later classification as a reproductive toxicant in the EU in 2009. In a considerable number of samples collected before 2002 health based guidance values (BE, HBM I) have been exceeded for DnBP (27.2%) and DEHP (2.3%) but also in recent samples some individual exceedances can still be observed (DEHP 1.0%). A decrease in concentration for all low molecular weight phthalates, labelled or not, was seen in the most recent years of sampling. For the high molecular weight phthalates, DEHP seems to have been substituted in part by di-isononyl phthalate (DiNP), but DiNP metabolite levels have also been declining in the last years. Probably, non-phthalate alternatives increasingly take over for the phthalates in Germany. A comparison with NHANES (National Health and Nutrition Examination Survey) data from the United States covering the years 1999 to 2012 revealed both similarities and differences in phthalate exposure between Germany and the US. Exposure to critical phthalates has decreased in both countries with metabolite levels more and more aligning with each other, but high molecular weight phthalates substituting DEHP (such as DiNP) seem to become more important in the US than in Germany.
An intensive study was conducted to provide data on intra- and inter-individual variation in urinary excretion of a series of ingredients in personal care products (parabens, triclosan, ...benzophenones) and bisphenol A (BPA, not expected to be an ingredient) in 8 volunteers over 6 days. Exposure diaries recorded use of personal care products with identified target analytes as ingredients. Participants' usual products were replaced with products without the target analytes for 2 of the 6 days. Urine void volumes and times were recorded. Methyl, ethyl, and n-propylparabens, triclosan, benzophenone-3, and BPA were frequently detected (≥70% of samples). Urinary concentrations of the parabens and triclosan were lower on product replacement days. First morning void concentrations correlated moderately to highly with 24-h composite concentrations for all analytes. Intraclass correlation coefficients (ICCs) for spot samples collected on days with usual product use were low for BPA (0.15), moderate for n-propylparaben and methylparaben (0.39 and 0.56, respectively), and high for ethylparaben, benzophenone-3, and triclosan (0.76, 0.81, and 0.934, respectively); ICCs were consistently higher on the basis of cr-adjusted concentrations. Hydration status adjustment methods were assessed by comparing unadjusted and adjusted concentrations to urinary excretion rates (ER, ng/kg-h) for all analytes and samples. Specific gravity-adjusted concentrations correlated slightly better with ER than creatinine-adjusted concentrations. Within-individual variation in biomarker concentrations was highest for methyl and ethylparabens (2 orders of magnitude variation in spot sample concentrations) and lower for the other analytes (1–1.5 orders of magnitude). This dataset provides insight into the design and interpretation of urinary biomonitoring studies for non-persistent chemicals.
•Determination of two oxidized metabolites of nonylphenol in human urine.•LC-MS/MS coupled with turbulent flow chromatography for online sample clean-up.•Stable isotope dilution analysis using custom ...synthesized standards.•Pilot study detects widespread NP exposure in the general German population (n = 34)•OH-NP & oxo-NP quantifiable in 94% and 47% of urine samples of this pilot study.
Nonylphenol (NP) is an endocrine disrupting and ecotoxic substance that has been detected in a variety of environmental matrices. It is utilized for the production of non-ionic nonylphenol ethoxylate (NPEO) detergents and other high production volume chemicals. Human biomonitoring data are scarce and mostly limited to the non-oxidized NP, which is ubiquitous in the (laboratory) environment and susceptible to external contamination. Here, we describe a sensitive, precise, accurate and rugged analytical method for the determination of OH-NP and oxo-NP, two potential alkyl-chain-oxidized metabolites of NP in human urine. We used single isomer standards, obtained by custom synthesis, for the quantification of the sum of the respective isomers. After enzymatic hydrolysis of potential urinary phase II conjugates, urine samples were analyzed by online turbulent flow chromatography for analyte enrichment and matrix depletion coupled to reversed phase liquid chromatography with negative electrospray-ionization triple quadrupole tandem mass spectrometry detection (online-SPE-LC-MS/MS). Quantification was performed by stable isotope dilution analysis. Limits of quantification in urinary matrix were 0.5 µg/L for OH-NP and 0.25 µg/L for oxo-NP. Mean relative recoveries were 101–105% (OH-NP) and 112–117% (oxo-NP) and the method imprecision (CV) in matrix was below 5%. In spite of extensive use restrictions in the EU since 2003, we could quantify OH-NP and oxo-NP in 94% and 47% of spot urine samples from the general German population (n = 32) collected in 2014. Thus, both metabolites seem suitable as sensitive and specific urinary biomarkers of NP exposure for future human biomonitoring population studies. Currently this method is used to quantitatively investigate human NP metabolism and to derive urinary metabolite excretion fractions that can be used to calculate external doses based on urinary biomarker concentrations.
Parabens are antimicrobial preservatives used in a wide range of consumer products such as personal care products, cosmetics, pharmaceuticals, and food. Consequently, the general population is ...ubiquitously exposed to these substances via dermal absorption, ingestion, and inhalation. Parabens promote estrogenic activity and are hence under assessment as endocrine disrupting substances. Urine samples from 3- to 17-year-old children and adolescents (N = 516) living in Germany were analysed for concentrations of nine parabens in the population representative German Environmental Survey for Children and Adolescents 2014–2017 (GerES V). Detection rates and urinary concentrations of the parabens decreased with increasing length of the alkyl chain. Methyl paraben was quantified in 97% of the samples with a geometric mean (GM) concentration of 7.724 μg/L (6.714 μg/gcreatinine), ethyl paraben was quantified in 69% (GM: 0.943 μg/L and 0.825 μg/gcrea), and n-propyl paraben in 31% (GM: 0.563 μg/L and 0.493 μg/gcrea). Concentrations of iso-propyl paraben, butyl paraben, iso-butyl paraben, and benzyl paraben were below the limit of quantification in most samples. Pentyl paraben and heptyl paraben were not detected in any of the samples. Paraben concentrations in urine were found to be associated with frequent usage of leave-on personal care products and cosmetics. Cumulative exposure to parabens (back-calculated daily intakes, expressed as hazard index) was found to be on a level raising concern in up to 14% of the population, mainly driven by n-propyl paraben, and depending on the level of conservativeness and point-of departures used for calculation.
•First representative exposure data on nine parabens for 3-17-year-olds in Germany.•Ubiquitous exposure of children and adolescents to several parabens.•Leave-on cosmetics associated with higher paraben exposure than rinse-off products.•Hazard index exceeding 1 in up to 14% of the population.•Lower exposure in Germany than in the US, Canada, and South Korea.
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The UV filters octocrylene (OC) and 2-ethylhexyl salicylate (EHS) are commonly used in sunscreens and frequently detected in environmental media. However, knowledge on human exposures ...is scarce.
In this human biomonitoring (HBM) study, we analyzed concentrations of exposure biomarkers specific to OC (CPAA, DOCCA, 5OH-OC) and EHS (5OH-EHS, 5oxo-EHS, 5cx-EPS) in 24-h urine samples (n = 420) from the German Environmental Specimen Bank (ESB). These samples were collected from German students (20–29 years; 30 males/30 females per year) between 1996 and 2020 (4-year intervals; collection in winter).
We found continuously increasing OC and EHS exposures (Jonckheere-Terpstra; p < 0.001) documented by very few to no samples with concentrations of the most sensitive biomarkers CPAA and 5cx-EPS above the limit of quantification (LOQ) in 1996 (5 % and 0 %, respectively) and reaching 100 % and 93 % above the LOQ in 2016, with median concentrations of 4.79 and 0.071 µg/L, respectively. In 2020, biomarker concentrations slightly decreased to 3.12 µg/L CPAA (97 %>LOQ) and 0.060 µg/L 5cx-EPS (88 %>LOQ). This general trend was confirmed by the other biomarkers, however at lower detection rates. Based on metabolite excretion in the 24-h urine samples and human toxicokinetic data, we calculated maximum daily intakes (DI) of 17 µg/(kg bw * d) OC and 59 µg/(kg bw * d) EHS. Based on a derived no-effect level (DNEL) of 0.8 mg/(kg bw * d), the OC exposures of individuals in our study did not indicate any health risk. Similarly, for EHS all biomarker concentrations were well below the HBM-I values of 12 µg/L 5OH-EHS and 11 µg/L 5cx-EPS.
Our data proves the general applicability of specific OC and EHS metabolites for HBM in the general population and shows clearly increasing exposures. Higher (co-)exposures must be expected in populations with increased sunscreen use such as (summer) vacationers, children and outdoor workers.
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