German Environmental Specimen Bank: 24-hour urine samples from 1999 to 2017 reveal rapid increase in exposure to the para-phthalate plasticizer di(2-ethylhexyl) terephthalate (DEHTP)

Phthalates and substitute plasticizers: Main achievements from the European human biomonitoring initiative HBM4EU

Phthalates and the substitute plasticizer DINCH belong to the first group of priority substances investigated by the European Human Biomonitoring Initiative (HBM4EU) to answer policy-relevant questions and safeguard an efficient science-to-policy transfer of results. Human internal exposure levels were assessed using two data sets from all European regions and Israel. The first collated existing human biomonitoring (HBM) data (2005-2019). The second consisted of new data generated in the harmonized "HBM4EU Aligned Studies" (2014-2021) on children and teenagers for the ten most relevant phthalates and DINCH, accompanied by a quality assurance/quality control (QA/QC) program for 17 urinary exposure biomarkers. Exposures differed between countries, European regions, age groups and educational levels. Toxicologically derived Human biomonitoring guidance values (HBM-GVs) were exceeded in up to 5% of the participants of the HBM4EU Aligned Studies. A mixture risk assessment (MRA) including five reprotoxic phthalates (DEHP, DnBP, DiBP, BBzP, DiNP) revealed that for about 17% of the children and teenagers, health risks cannot be excluded. Concern about male reproductive health emphasized the need to include other anti-androgenic substances for MRA. Contaminated food and the use of personal care products were identified as relevant exposure determinants paving the way for new regulatory measures. Time trend analyses verified the efficacy of regulations: especially for the highly regulated phthalates exposure dropped significantly, while levels of the substitutes DINCH and DEHTP increased. The HBM4EU e-waste study, however, suggests that workers involved in e-waste management may be exposed to higher levels of restricted phthalates. Exposure-effect association studies indicated the relevance of a range of endpoints. A set of HBM indicators was derived to facilitate and accelerate science-to-policy transfer. Result indicators allow different groups and regions to be easily compared. Impact indicators allow health risks to be directly interpreted. The presented results enable successful science-to-policy transfer and support timely and targeted policy measures.

Association of Di(2-ethylhexyl) Terephthalate and Its Metabolites with Nonalcoholic Fatty Liver Disease: An Epidemiology and Toxicology Study

As an alternative plasticizer to conventional phthalates, di(2-ethylhexyl) terephthalate (DEHTP) has attracted considerable concerns, given its widespread detection in the environment and humans. However, the potential toxicity, especially liver toxicity, posed by DEHTP remains unclear. In this study, based on the 2017-2018 National Health and Nutrition Examination Survey, two metabolites of DEHTP, i.e., mono(2-ethyl-5-hydroxyhexyl) terephthalate (MEHHTP) and mono(2-ethyl-5-carboxypentyl) terephthalate (MECPTP), were found to be present in the urine samples of nearly all representative U.S. adults. Moreover, a positive linear correlation was observed between the concentrations of the two metabolites and the risk of nonalcoholic fatty liver disease (NAFLD) in the population. Results of weighted quantile sum and Bayesian kernel machine regression indicated that MEHHTP contributed a greater weight to the risk of NAFLD in comparison with 12 conventional phthalate metabolites. In vitro experiments with hepatocyte HepG2 revealed that MEHHTP exposure could increase lipogenic gene programs, thereby promoting a dose-dependent hepatic lipid accumulation. Activation of liver X receptor α may be an important regulator of MEHHTP-induced hepatic lipid disorders. These findings provide new insights into the liver lipid metabolism toxicity potential of DEHTP exposure in the population.

Reducing Transdermal Uptake of Semivolatile Plasticizers from Indoor Environments: A Clothing Intervention

Models and laboratory studies suggest that everyday clothing influences the transdermal uptake of semivolatile organic compounds, including phthalate plasticizers, from indoor environments. However, this effect has not been documented in environmental exposure settings. In this pilot study, we quantified daily excretion of 17 urinary metabolites (μg/day) for phthalates and phthalate alternatives in nine participants during 5 days. On Day 0, baseline daily excretion was determined in participants' urine. Starting on Day 1, participants refrained from eating phthalate-heavy foods and using personal care products. On Days 3 and 4, participants wore precleaned clothing as an exposure intervention. We observed a reduction in the daily excretion of phthalates during the intervention; mono-n-butyl phthalate, monoisobutyl phthalate (MiBP), and monobenzyl phthalate were significantly reduced by 35, 38, and 56%, respectively. Summed metabolites of di(2-ethylhexyl)phthalate (DEHP) were also reduced (27%; not statistically significant). A similar reduction among phthalate alternatives was not observed. The daily excretion of MiBP during the nonintervention period strongly correlated with indoor air concentrations of diisobutyl phthalate (DiBP), suggesting that inhalation and transdermal uptake of DiBP from the air in homes are dominant exposure pathways. The results indicate that precleaned clothing can significantly reduce environmental exposure to phthalates and phthalate alternatives.

Endocrine-disrupting chemicals and male reproductive health

Modifiable factors, such as environmental exposures, can impact human fertility. The objective of this review is to summarize the potential effects of exposure to important endocrine-disrupting chemicals on male reproductive health. Most experimental and animal data demonstrate strong evidence for the negative effects of exposure to phenols, phthalates, pesticides, and perfluoroalkyl and polyfluoroalkyl substances on male reproductive health. Although evidence of negative associations in humans was overall strong for phthalates and pesticides, limited and inconclusive relationships were found for the other examined chemical biomarkers. Reasons for the discrepancies in results include but are not limited to, differences in study populations, exposure concentrations, number of samples collected, sample sizes, study design, and residual confounding. Additional studies are needed, particularly for newer phenols and perfluoroalkyl and polyfluoroalkyl substances, given the scarce literature on the topic and increasing exposures over time.

Assessment of the plasticizer exposure of hospital workers regularly handling medical devices: A pilot study

Plastic medical devices, e.g. infusion sets, blood bags or tubing material, that are used manifold in the medical treatment of hospital patients, usually contain considerable amounts of plasticizers. Whereas several studies showed highly elevated inner plasticizer levels of patients treated with plasticized medical devices, little is known about the exposure situation of hospital staff. The present pilot study aimed to evaluate the urinary plasticizer metabolite levels of selected hospital workers of the blood bank (medical technical assistants, MTA) and of perfusionists that are regularly handling plasticized medical devices in order to estimate the work-related amount of the inner individual plasticizer exposure. The study subjects were asked to collect pre- and post-shift spot urine samples over the course of a working week, that were subsequently analyzed for selected urinary metabolites of the plasticizers DEHP, DINCH, DEHTP and TEHTM. Although the observed differences were rather low, a differentiated approach revealed a perceptible impact of the respective workplace environment on the individual urinary plasticizer metabolite levels. Thus, the group of blood bank MTA showed significantly elevated increment levels of urinary DEHP and DINCH metabolites, while the group of perfusionists, showed a considerable higher detection frequency of the main urinary TEHTM metabolite. All in all, however, it can be cautiously concluded by the results of the presented pilot study that a regular handling of plasticized medical devices by hospital employees (via inhalation or dermal contact) contributes demonstrably but yet only marginally to the individual internal plasticizer exposure.

The plastic health map: A systematic evidence map of human health studies on plastic-associated chemicals

BACKGROUND

The global production and use of plastic materials has increased dramatically since the 1960s and there is increasing evidence of human health impacts related to exposure to plastic-associated chemicals. There is, however, no comprehensive, regulatory, post-market monitoring for human health effects of plastic-associated chemicals or particles and it is unclear how many of these have been investigated for effects in humans, and therefore what the knowledge gaps are.

OBJECTIVE

To create a systematic evidence map of peer-reviewed human studies investigating the potential effects of exposure to plastic-associated particles/chemicals on health to identify research gaps and provide recommendations for future research and regulation policy.

METHODS

Medline and Embase databases were used to identify peer-reviewed primary human studies published in English from Jan 1960 - Jan 2022 that investigated relationships between exposures to included plastic-associated particles/chemicals measured and detected in bio-samples and human health outcomes. Plastic-associated particles/chemicals included are: micro and nanoplastics, due to their widespread occurrence and potential for human exposure; polymers, the main building blocks of plastic; plasticizers and flame retardants, the two most common types of plastic additives with the highest concentration ranges in plastic materials; and bisphenols and per- or polyfluoroalkyl substances, two chemical classes of known health concern that are common in plastics. We extracted metadata on the population and study characteristics (country, intergenerational, sex, age, general/special exposure risk status, study design), exposure (plastic-associated particle/chemical, multiple exposures), and health outcome measures (biochemical, physiological, and/or clinical), from which we produced the interactive database 'Plastic Health Map' and a narrative summary.

RESULTS

We identified 100,949 unique articles, of which 3,587 met our inclusion criteria and were used to create a systematic evidence map. The Plastic Health Map with extracted metadata from included studies are freely available at https://osf.io/fhw7d/ and summary tables, plots and overall observations are included in this report.

CONCLUSIONS

We present the first evidence map compiling human health research on a wide range of plastic-associated chemicals from several different chemical classes, in order to provide stakeholders, including researchers, regulators, and concerned individuals, with an efficient way to access published literature on the matter and determine knowledge gaps. We also provide examples of data clusters to facilitate systematic reviews and research gaps to help direct future research efforts. Extensive gaps are identified in the breadth of populations, exposures and outcomes addressed in studies of potential human health effects of plastic-associated chemicals. No studies of the human health effects of micro and/or nanoplastics were found, and no studies were found for 26/1,202 additives included in our search that are of known hazard concern and confirmed to be in active production. Few studies have addressed recent "substitution" chemicals for restricted additives such as organophosphate flame retardants, phthalate substitutes, and bisphenol analogues. We call for a paradigm shift in chemical regulation whereby new plastic chemicals are rigorously tested for safety before being introduced in consumer products, with ongoing post-introduction biomonitoring of their levels in humans and health effects throughout individuals' life span, including in old age and across generations.

Exposure Trends to the Non-phthalate Plasticizers DEHTP, DINCH, and DEHA in Children from 2012 to 2017: The Hokkaido Study

Phthalates owing to their endocrine-disrupting effects are regulated in certain products, leading to their replacement with substitutions such as di-2-ethylhexyl terephthalate (DEHTP), 1,2-cyclohexane dicarboxylic acid di(isononyl) ester (DINCH), and di(2-ethylhexyl) adipate (DEHA). However, information on human exposure to these substitutes, especially in susceptible subpopulations such as children, is limited. Thus, we examined the levels and exposure trends of DEHTP, DINCH, and DEHA metabolites in 7 year-old Japanese school children. In total, 180 urine samples collected from 2012 to 2017 were used to quantify 10 DEHTP, DINCH, and DEHA metabolites via isotope dilution liquid chromatography with tandem mass spectrometry. DEHTP and DINCH metabolites were detected in 95.6 and 92.2% of the children, respectively, and DEHA was not detected. This study, annually conducted between 2012 and 2017, revealed a significant (p < 0.05) 5-fold increase in DEHTP metabolites and a 2-fold increase in DINCH metabolites. However, the maximum estimated internal exposures were still below the health-based guidance and toxicological reference values. Exposure levels to DEHTP and DINCH have increased considerably in Japanese school children. DEHA is less relevant. Future studies are warranted to closely monitor the increasing trend in different aged and larger populations and identify the potential health effects and sources contributing to increasing exposure and intervene if necessary.

Associations of phthalates, phthalate replacements, and their mixtures with eicosanoid biomarkers during pregnancy

Humans are exposed to complex mixtures of phthalates. Gestational exposure to phthalates has been linked to preeclampsia and preterm birth through potential pathways such as endocrine disruption, oxidative stress, and inflammation. Eicosanoids are bioactive signaling lipids that are related to a variety of homeostatic and inflammatory processes. We investigated associations between urinary phthalates and their mixtures with plasma eicosanoid levels during pregnancy using the PROTECT cohort in Puerto Rico (N = 655). After adjusting for covariates, we estimated pair-wise associations between the geometric mean of individual phthalate metabolite concentrations across pregnancy and eicosanoid biomarkers using multivariable linear regression. We used bootstrapping of adaptive elastic net regression (adENET) to evaluate phthalate mixtures associated with eicosanoids and subsequently create environmental risk scores (ERS) to represent weighted sums of phthalate exposure for each individual. After adjusting for false-discovery, in single-pollutant analysis, 14 of 20 phthalate metabolites or parent compound indices showed significant and primarily negative associations with multiple eicosanoids. In our mixture analysis, associations with several metabolites of low molecular weight phthalates - DEP, DBP, and DIBP - became prominent. Additionally, MEHHTP and MECPTP, metabolites of a new phthalate replacement, DEHTP, were selected as important predictors for determining the concentrations of multiple eicosanoids from different pathway groups. A unit increase in phthalate ERS derived from bootstrapping of adENET was positively associated with several eicosanoids mainly from Cytochrome P450 pathway. For example, an increase in ERS was associated with 11(S)-HETE (β = 1.6, 95% CI: 0.020, 3.180), (±)11,12-DHET (β = 2.045, 95% CI: 0.250, 3.840), 20(S)-HETE (β = 0.813, 95% CI: 0.147, 1.479), and 9 s-HODE (β = 2.381, 95% CI: 0.657, 4.104). Gestational exposure to phthalates and phthalate mixtures were associated with eicosanoid levels during pregnancy. Results from the mixture analyses underscore the complexity of physiological impacts of phthalate exposure and call for further in-depth studies to examine these relationships.

Effects of di-(2-ethylhexyl) terephthalate on hypothalamus-pituitary-gonad axis in adult zebrafish

Di-(2-ethylhexyl) terephthalate (DEHTP) is frequently used in food packaging and medical devices as an alternative to di-(2-ethylhexyl) phthalate (DEHP). In this study, zebrafish pairs were exposed to DEHTP for 21 d and the effects on fertility, sex hormone levels, vitellogenin levels, and transcription of genes along the hypothalamic-pituitary-gonad axis were evaluated. Results showed that mean egg numbers were significantly reduced in the 30 and 300 μg/L DEHTP groups. The adverse effects of DEHTP on hormones and gene transcripts were more prominent in males than in females. In male fish, the gonadosomatic index, hepatosomatic index, and vitellogenin concentration were significantly increased. The results of a significant decrease in testosterone (T) and an increase in the 17β-estradiol (E2)/T ratio in males exposed to 3-300 μg/L DEHTP suggest that the endocrine potential of DEHTP is similar that of DEHP. In females, genes related to gonadotropin-releasing hormone and gonadotropin were up-regulated while E2 was significantly down-regulated. These findings suggest that positive E2 feedback mechanisms in the hypothalamus and pituitary gland are activated to balance sex hormones. The effects of chronic exposure to DEHTP on the neuroendocrine system require further investigation.

Associations of urinary metabolite concentrations of phthalates and phthalate replacements with body composition from mid-childhood to early adolescence

BACKGROUND

Phthalates may adversely influence body composition by lowering anabolic hormones and activating peroxisome-proliferator activated receptor gamma. However, data are limited in adolescence when body mass distributions rapidly change and bone accrual peaks. Also, potential health effects of certain phthalate/replacements [e.g., di-2-ethylhexyl terephthalate (DEHTP)] have not been well studied.

METHODS

Among 579 children in the Project Viva cohort, we used linear regression to evaluate associations of urinary concentrations of 19 phthalate/replacement metabolites from mid-childhood (median: 7.6 years; 2007-2010) with annualized change in areal bone mineral density (aBMD) and lean, total fat, and truncal fat mass as measured by dual-energy X-ray absorptiometry between mid-childhood and early adolescence (median: 12.8 years). We used quantile g-computation to assess associations of the overall chemical mixture with body composition. We adjusted for sociodemographics and tested for sex-specific associations.

RESULTS

Urinary concentrations were highest for mono-2-ethyl-5-carboxypentyl phthalate [median (IQR): 46.7 (69.1) ng/mL]. We detected metabolites of most replacement phthalates in a relatively small number of participants [e.g., 28% for mono-2-ethyl-5-hydrohexyl terephthalate (MEHHTP; metabolite of DEHTP)]. Detectable (vs. non-detectable) MEHHTP was associated with less bone and greater fat accrual in males and greater bone and lean mass accrual in females [e.g., change in aBMD Z-score/year (95% CI): -0.049 (-0.085, -0.013) in males versus 0.042 (0.007, 0.076) in females; pinteraction<0.01]. Children with higher concentrations of mono-oxo-isononyl phthalate and mono-3-carboxypropyl phthalate (MCPP) had greater bone accrual. Males with higher concentrations of MCPP and mono-carboxynonyl phthalate had greater accrual of lean mass. Other phthalate/replacement biomarkers, and their mixtures, were not associated with longitudinal changes in body composition.

CONCLUSIONS

Concentrations of select phthalate/replacement metabolites in mid-childhood were associated with changes in body composition through early adolescence. As use of phthalate replacements such as DEHTP may be increasing, further investigation can help better understand the potential effects of early-life exposures.

Temporal trends and predictors of phthalate, phthalate replacement, and phenol biomarkers in the LIFECODES Fetal Growth Study

BACKGROUND

Exposure to many phthalates and phenols is declining as replacements are introduced. There is little information on temporal trends or predictors of exposure to these newer compounds, such as phthalate replacements, especially among pregnant populations.

OBJECTIVE

Examine temporal trends and predictors of exposure to phthalates, phthalate replacements, and phenols using single- and multi-pollutant approaches.

METHODS

We analyzed data from 900 singleton pregnancies in the LIFECODES Fetal Growth Study, a nested case-cohort with recruitment from 2007 to 2018. We measured and averaged concentrations of 12 phthalate metabolites, four phthalate replacement metabolites, and 12 phenols in urine at three timepoints during pregnancy. We visualized and analyzed temporal trends and predictors of biomarker concentrations. To examine chemical mixtures, we derived clusters of individuals with shared exposure profiles using a finite mixture model and examined temporal trends and predictors of cluster assignment.

RESULTS

Exposure to phthalates and most phenols declined across the study period, while exposure to phthalate replacements (i.e., di(isononyl) cyclohexane-1,2-dicarboxylic acid, diisononyl ester [DINCH] and di-2-ethylhexyl terephthalate [DEHTP]) and bisphenol S (BPS) increased. For example, the sum of DEHTP biomarkers increased multiple orders of magnitude, with an average concentration of 0.92 ng/mL from 2007 to 2008 and 61.9 ng/mL in 2017-2018. Biomarkers of most chemical exposures varied across sociodemographic characteristics, with the highest concentrations observed in non-Hispanic Black or Hispanic participants relative to non-Hispanic White participants. We identified five clusters with shared exposure profiles and observed temporal trends in cluster membership. For example, at the end of the study period, a cluster characterized by high exposure to phthalate replacements was the most prevalent.

SIGNIFICANCE

In a large and well-characterized pregnancy cohort, we observed exposure to phthalate replacements and BPS increased over time while exposure to phthalates and other phenols decreased. Our results highlight the changing nature of exposure to consumer product chemical mixtures.

Urinary excretion of phthalates and the substitutes DINCH and DEHTP in Danish young men and German young adults between 2000 and 2017 - A time trend analysis

Over the last twenty-five years it has become evident that exposure to several phthalates can have adverse effects on human health, such as endocrine disruption. This led to a series of EU regulations that resulted in a decrease in the production volumes of the restricted phthalates and an increased production of substitutes. The current study describes the impact of regulations and changes in production and use of phthalates and their substitutes on internal exposure patterns in two European populations since the beginning of the 2000'ies. Using harmonised data from young adults in Denmark (Danish Young Men Study, n = 1,063, spot urine) and Germany (Environmental Specimen Bank, n = 878, 24-h urine) with repeated cross-sectional design (3-11 cycles per biomarker) we applied Locally Estimated Scatterplot Smoothing (LOESS) and Generalized Linear Models (GLMs) to estimate time trends and the role of covariates on the trend (e.g. age, BMI). Time trends of daily excretion (μg/24h) are comparable between the two samples for the regulated (DEHP, BBzP, DiNP, DnBP, DiBP, DiDP/DPHP) as well as the non-regulated substances (DMP, DEP, DINCH, DEHTP) although the rate of change differ for some of the compounds. GLM results indicate that the daily excretion of the most regulated phthalates has decreased over time (DEHP yearly about 12-16%, BBzP 5%, DnBP 0.3-17%, and DiBP 4-12%). Interestingly, also the non-regulated phthalates DMP and DEP decreased by 6-18% per year. In sharp contrast, the phthalate substitutes DINCH and DEHTP show very steep annual increases (∼10-68% and ∼100%, respectively) between 2009 and 2017. We did not find an effect of age, sex, BMI, or education on the time trend. The present study provides comparable insights into how exposure to phthalates and two of their substitutes have changed over the last two decades in Germany and Denmark.

Time-trends in human urinary concentrations of phthalates and substitutes DEHT and DINCH in Asian and North American countries (2009-2019)

BACKGROUND

Many phthalates are environmental pollutants and toxic to humans. Following phthalate regulations, human exposure to phthalates has globally decreased with time in European countries, the US and Korea. Conversely, exposure to their substitutes DEHT and/or DINCH has increased. In other countries, including China, little is known on the time-trends in human exposure to these plasticizers.

OBJECTIVE

We aimed to estimate time-trends in the urinary concentrations of phthalates, DEHT, and DINCH metabolites, in general population from non-European countries, in the last decade.

METHODS

We compiled human biomonitoring (HBM) data from 123 studies worldwide in a database termed "PhthaLit". We analyzed time-trends in the urinary concentrations of the excreted metabolites of various phthalates as well as DEHT and DINCH per metabolite, age group, and country/region, in 2009-2019. Additionally, we compared urinary metabolites levels between continents.

RESULTS

We found solid time-trends in adults and/or children from the US, Canada, China and Taiwan. DEHP metabolites decreased in the US and Canada. Conversely in Asia, 5oxo- and 5OH-MEHP (DEHP metabolites) increased in Chinese children. For low-weight phthalates, the trends showed a mixed picture between metabolites and countries. Notably, MnBP (a DnBP metabolite) increased in China. The phthalate substitutes DEHT and DINCH markedly increased in the US.

SIGNIFICANCE

We addressed the major question of time-trends in human exposure to phthalates and their substitutes and compared the results in different countries worldwide.

IMPACT

Phthalates account for more than 50% of the plasticizer world market. Because of their toxicity, some phthalates have been regulated. In turn, the consumption of non-phthalate substitutes, such as DEHT and DINCH, is growing. Currently, phthalates and their substitutes show high detection percentages in human urine. Concerning time-trends, several studies, mainly in Europe, show a global decrease in phthalate exposure, and an increase in the exposure to phthalate substitutes in the last decade. In this study, we address the important question of time-trends in human exposure to phthalates and their substitutes and compare the results in different countries worldwide.

Monitoring the exposure to ethoxyquin between 2000 and 2021 in urine samples from the German Environmental Specimen Bank

Human Biomonitoring (HBM) of emerging chemicals gained increasing attention within the EU in recent years. After evaluating the metabolism, we established a new HBM method for ethoxyquin (EQ), a feed additive, which was banned in 2017 due to concerns regarding the possible exposure of the general population to it and its highly toxic precursor p-phenetidine. The method was applied to 250 urine samples from the Environmental Specimen Bank collected between 2000 and 2021. The major metabolite EQI was quantified in the majority of the study samples illustrating the ubiquitous exposure of the non-occupationally exposed population. A rather constant exposure was observed until 2016 with a significant decline from 2016 to 2021. This drop falls within the EU wide ban of the chemical as a feed additive from June 2017 which led to a gradual removal until its complete suspension in June 2020. The daily intake (DI) was evaluated with respect to the reported derived no-effect level (DNEL) to estimate the potential health risks from EQ exposure. The median DI of 0.0181 µg/kg bw/d corresponds to only 0.01 % of the DNEL. Even the observed maxima up to 13.1 µg/kg bw/d only accounted for 10 % of the DNEL. Nevertheless, the values suggest a general exposure with the risk of higher burden in a low fraction of the population. In regard to the EQ associated intake of the carcinogen and suspected mutagen p-phenetidine, this level of exposure cannot be evaluated as safe. The recent decrease and the broad exposure substantiate the need for future HBM campaigns in population representative studies to further investigate the observed reductions, potentially find highly exposed subgroups and clarify the impact of the ban as feed additive on EQ exposure.

Simultaneous and sensitive determination of the main metabolites of the plasticizer DEHP and its substitutes DEHTP, DINCH and TEHTM in human urine by coupling of on-line SPE, UHPLC and tandem mass spectrometry

With the prominent but toxicologically critical plasticizer di-(2-ethylhexyl) phthalate (DEHP) declining, alternative plasticizers are increasingly used leading to a continuously more diverse exposure situation of humans with multiple plasticizers. Therefore, an on-line SPE-LC-MS/MS method for the simultaneous determination of the most relevant urinary biomarkers of exposure to DEHP and the alternative plasticizers 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), di-(2-ethylhexyl) terephthalate (DEHTP) and tri-(2-ethylhexyl) trimellitate (TEHTM) was developed. The method is characterized by a high sensitivity with limits of detection ranging from 0.006 to 0.047 μg L^-1 combined with an easy and straightforward sample preparation procedure. The wide linear working range of the method enables a reliable determination of analyte background levels in the general population as well as its potential use for monitoring studies investigating elevated plasticizer exposure settings. The method was successfully applied to urine samples from ten volunteers without occupational exposure to plasticizers revealing ubiquitous background exposure levels of the common plasticizers DEHP, DEHTP and DINCH.

Personal care product use and lifestyle affect phthalate and DINCH metabolite levels in teenagers and young adults

Humans are widely exposed to phthalates and their novel substitutes, and considering the negative health effects associated with some phthalates, it is crucial to understand population levels and exposure determinants. This study is focused on 300 urine samples from teenagers (aged 12-17) and 300 from young adults (aged 18-37) living in Czechia collected in 2019 and 2020 to assess 17 plasticizer metabolites as biomarkers of exposure. We identified widespread phthalate exposure in the study population. The diethyl phthalate metabolite monoethyl phthalate (MEP) and three di (2-ethylhexyl) phthalate metabolites were detected in the urine of >99% of study participants. The highest median concentrations were found for metabolites of low-molecular-weight (LMW) phthalates: mono-n-butyl phthalate (MnBP), monoisobutyl phthalate (MiBP) and MEP (60.7; 52.6 and 17.6 μg/L in young adults). 1,2-cyclohexanedicarboxylic acid diisononyl ester (DINCH) metabolites were present in 68.2% of the samples with a median of 1.24 μg/L for both cohorts. Concentrations of MnBP and MiBP were similar to other European populations, but 5-6 times higher than in populations in North America. We also observed large variability in phthalate exposures within the study population, with 2-3 orders of magnitude differences in urinary metabolites between high and low exposed individuals. The concentrations varied with season, gender, age, and lifestyle factors. A relationship was found between high levels of MEP and high overall use of personal care products (PCPs). Cluster analysis suggested that phthalate exposures depend on season and multiple lifestyle factors, like time spent indoors and use of PCPs, which combine to lead to the observed widespread presence of phthalate metabolites in both study populations. Participants who spent more time indoors, particularly noticeably during colder months, had higher levels of high-molecular weight phthalate metabolites, whereas participants with higher PCP use, particularly women, tended to have higher concentration of LMW phthalate metabolites.

Medical devices as a source of phthalate exposure: a review of current knowledge and alternative solutions

Phthalates are a group of phthalic acid esters used as plasticisers in a large number of products to improve their flexibility, softness, and extensibility. Their wide use in medical devices, however, raises a lot of concern, as they can enter the organism and have toxic effects on human liver, thyroid, kidneys, lungs, reproductive, endocrine, nervous, and respiratory system and are associated with asthma, obesity, autism, and diabetes. The aim of this review is to summarise current knowledge about phthalate migration from medical devices during different medical procedures and possible impact on patient health. It also looks at alternative plasticisers with supposedly lower migration rates and safer profile. Not enough is known about which and how many phthalates make part of medical devices or about the health impacts of alternative plasticisers or their migration rates.

Prenatal Exposures to Common Phthalates and Prevalent Phthalate Alternatives and Infant DNA Methylation at Birth

Phthalates are a diverse group of chemicals used in consumer products. Because they are so widespread, exposure to these compounds is nearly unavoidable. Recently, growing scientific consensus has suggested that phthalates produce health effects in developing infants and children. These effects may be mediated through mechanisms related to the epigenome, the constellation of mitotically heritable chemical marks and small compounds that guide transcription and translation. The present study examined the relationship between prenatal, first-trimester exposure of seven phthalates and epigenetics in two pregnancy cohorts (n = 262) to investigate sex-specific alterations in infant blood DNA methylation at birth (cord blood or neonatal blood spots). Prenatal exposure to several phthalates was suggestive of association with altered DNA methylation at 4 loci in males (all related to ΣDEHP) and 4 loci in females (1 related to ΣDiNP; 2 related to BBzP; and 1 related to MCPP) at a cutoff of q < 0.2. Additionally, a subset of dyads (n = 79) was used to interrogate the relationships between two compounds increasingly used as substitutions for common phthalates (ΣDINCH and ΣDEHTP) and cord blood DNA methylation. ΣDINCH, but not ΣDEHTP, was suggestive of association with DNA methylation (q < 0.2). Together, these results demonstrate that prenatal exposure to both classically used phthalate metabolites and their newer alternatives is associated with sex-specific infant DNA methylation. Research and regulatory actions regarding this chemical class should consider the developmental health effects of these compounds and aim to avoid regrettable substitution scenarios in the present and future.

Exposure to 15 phthalates and two substitutes (DEHTP and DINCH) assessed in trios of infants and their parents as well as longitudinally in infants exclusively breastfed and after the introduction of a mixed diet

OBJECTIVE

Several phthalates have been restricted/banned due to their adverse endocrine disrupting properties. The use of other phthalates and substitutes has increased. Here we examine the current exposure to phthalates in family trios comprised of infants and their parents and in infants exclusive breastfed and following introduction to a mixed diet.

METHODS

Metabolites of 15 phthalates and two substitutes, di(2-ethylhexyl)-teraphthalate (DEHTP) and diisononyl-cyclohexane-1,2-dicarboxylate (DINCH), were measured in urine samples collected from >100 infants and their parents and in paired urine samples collected from 67 infants, while they were exclusively breastfed and when they got mixed diet.

RESULTS

Among infants and their parents, metabolites of nine out of 15 phthalates and both substitutes were detected in >74% of all samples. Estimated daily intake (DI) calculated as µg/kg/day, showed similar exposure levels among infants and their parents for several of the substances, and infants were more exposed to DEHTP than their mothers. Significantly higher estimated DIs were observed for some low-molecular phthalates in infants exclusively breastfed. In contrast, comparable estimated DIs were observed for many other phthalates and DEHTP regardless of feeding status. For most of the substances, the within-family variation, was lower than the between-family variation. Likewise, the within-infant variation on exclusively breast vs. mixed diet was lower than the between-infant variation. Independent of food status, some infants were concurrently exposed to almost all the measured phthalates and substitutes in higher amounts than others.

CONCLUSION

Surprisingly, irrespective of diet status infants were exposed to several phthalates and substitutes some of which have been regulated for years. Exposure patterns and levels were similar in infants and their parents. Importantly, risk assessment based on new refined reference doses (RfD-AA) exceeded the safety level for anti-androgenic effects in a number of infants and parents, which is of concern.

Proficiency and Interlaboratory Variability in the Determination of Phthalate and DINCH Biomarkers in Human Urine: Results from the HBM4EU Project

A quality assurance/quality control program was implemented in the framework of the EU project HBM4EU to assess and improve the comparability of biomarker analysis and to build a network of competent laboratories. Four rounds of proficiency tests were organized for 15 phthalate and two DINCH urinary biomarkers (0.2–138 ng/mL) over a period of 18 months, with the involvement of 28 laboratories. A substantial improvement in performance was observed after the first round in particular, and by the end of the program, an average satisfactory performance rate of 90% was achieved. The interlaboratory reproducibility as derived from the participants’ results varied for the various biomarkers and rounds, with an average of 24% for the biomarkers of eight single-isomer phthalates (e.g., DnBP and DEHP) and 43% for the more challenging biomarkers of the mixed-isomer phthalates (DiNP, DiDP) and DINCH. When the reproducibility was based only on the laboratories that consistently achieved a satisfactory performance, this improved to 17% and 26%, respectively, clearly demonstrating the success of the QA/QC efforts. The program thus aided in building capacity and the establishment of a network of competent laboratories able to generate comparable and accurate HBM data for phthalate and DINCH biomarkers in 14 EU countries. In addition, global comparability was ensured by including external expert laboratories.

Urinary Concentrations of Major Phthalate and Alternative Plasticizer Metabolites in Children of Thailand, Indonesia, and Saudi Arabia, and Associated Risks

Phthalates are widely used in consumer products and are well-known for adverse endocrine outcomes. Di-(2-ethylhexyl) phthalate (DEHP), one of the most extensively used phthalates, has been rapidly substituted with alternative plasticizers in many consumer products. The aim of this study was to assess urinary phthalate and alternative plasticizer exposure and associated risks in children of three Asian countries with different geographical, climate, and cultural characteristics. Children were recruited from elementary schools of Saudi Arabia (n = 109), Thailand (n = 104), and Indonesia (n = 89) in 2017-2018, and their urine samples were collected. Metabolites of major phthalates and alternative plasticizers were measured in the urine samples by HPLC-MS/MS. Urinary metabolite levels differed substantially between the three countries. Metabolite levels of diisononyl phthalate (DiNP), diisodecyl phthalate (DiDP), di(2-ethylhexyl) terephthalate (DEHTP), and 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) were the highest in Saudi children: Median urinary concentrations of oxo-MiNP, OH-MiDP, 5cx-MEPTP, and OH-MINCH were 8.3, 8.4, 128.0, and 2.9 ng/mL, respectively. Urinary DEHP metabolite concentrations were the highest in the Indonesian children. The hazard index (HI) derived for the plasticizers with antiandrogenicity based reference doses (RfD_AA) was >1 in 86%, 80%, and 49% of the Saudi, Indonesian, and Thai children, respectively. DEHP was identified as a common major risk driver for the children of all three countries, followed by DnBP and DiBP depending on the country. Among alternative plasticizers, urinary DEHTP metabolites were detected at levels comparable to those of DEHP metabolites or higher among the Saudi children, and about 4% of the Saudi children exceeded the health based human biomonitoring (HBM)-I value. Priority plasticizers that were identified among the children of three countries warrant refined exposure assessment for source identification and relevant exposure reduction measures.

Maternal Phthalates Exposure and Blood Pressure during and after Pregnancy in the PROGRESS Study

BACKGROUND

Phthalate exposure is ubiquitous and may affect biological pathways related to regulators of blood pressure. Given the profound changes in vasculature during pregnancy, pregnant women may be particularly susceptible to the potential effects of phthalates on blood pressure.

OBJECTIVES

We examined associations of phthalate exposure during pregnancy with maternal blood pressure trajectories from mid-pregnancy through 72 months postpartum.

METHODS

Women with singleton pregnancies delivering a live birth in Mexico City were enrolled during the second trimester (n=892). Spot urine samples from the second and third trimesters were analyzed for 15 phthalate metabolites. Blood pressure and covariate data were collected over nine visits through 72 months postpartum. We used linear, logistic, and linear mixed models; latent class growth models (LCGMs); and Bayesian kernel machine regression to estimate the relationship of urinary phthalate biomarkers with maternal blood pressure.

RESULTS

As a joint mixture, phthalate biomarker concentrations during pregnancy were associated with higher blood pressure rise during mid-to-late gestation. With respect to individual biomarkers, second trimester concentrations of monobenzyl phthalate (MBzP) and di(2-ethylhexyl) phthalate biomarkers (ΣDEHP) were associated with higher third trimester blood pressure. Two trajectory classes were identified by LCGM, characterized by increasing blood pressure through 72 months postpartum ("increase-increase") or decreased blood pressure through 18 months postpartum with a gradual increase thereafter ("decrease-increase"). Increasing exposure to phthalate mixtures during pregnancy was associated with higher odds of being in the increase-increase class. Similar associations were observed for mono-2-ethyl-5-carboxypentyl terephthalate (MECPTP) and dibutyl phthalate (ΣDBP) biomarkers. When specific time periods were examined, we observed specific temporal relationships were observed for ΣDEHP, MECPTP, MBzP, and ΣDBP.

DISCUSSION

In our cohort of pregnant women from Mexico City, exposure to phthalates and phthalate biomarkers was associated with higher blood pressure during late pregnancy, as well as with long-term changes in blood pressure trajectories. https://doi.org/10.1289/EHP8562.

Phthalates and Alternative Plasticizers Differentially affect Phenotypic Parameters in Gonadal Somatic and Germ Cell Lines

The developmental and reproductive toxicity associated with exposure to phthalates has motivated a search for alternatives. However, there is limited knowledge regarding the adverse effects of some of these chemicals. We used high-content imaging to compare the effects of mono (2-ethylhexyl) phthalate (MEHP) with six alternative plasticizers: di-2-ethylhexyl terephthalate (DEHTP); diisononyl-phthalate (DINP); di-isononylcyclohexane-1,2-dicarboxylate (DINCH); 2-ethylhexyl adipate (DEHA); 2,2,4-trimethyl 1,3-pentanediol diisobutyrate (TXIB) and di-iso-decyl-adipate (DIDA). A male germ spermatogonial cell line (C18-4), a Sertoli cell line (TM4) and two steroidogenic cell lines (MA-10 Leydig and KGN granulosa) were exposed for 48h to each chemical (0.001-100 μM). Cell images were analyzed to assess cytotoxicity and effects on phenotypic endpoints. Only MEHP (100 μM) was cytotoxic and only in C18-4 cells. However, several plasticizers had distinct phenotypic effects in all four cell lines. DINP increased Calcein intensity in C18-4 cells, whereas DIDA induced oxidative stress. In TM4 cells, MEHP, and DINCH affected lipid droplet numbers, while DEHTP and DINCH increased oxidative stress. In MA-10 cells, MEHP increased lipid droplet areas and oxidative stress; DINP decreased the number of lysosomes, while DINP, DEHA and DIDA altered mitochondrial activity. In KGN cells, MEHP, DINP and DINCH increased the number of lipid droplets, whereas DINP decreased the number of lysosomes, increased oxidative stress and affected mitochondria. The Toxicological Priority Index (ToxPi) provided a visual illustration of the cell line specificity of the effects on phenotypic parameters. The lowest administered equivalent doses were observed for MEHP. We propose that this approach may assist in screening alternative plasticizers.

Human Metabolism and Urinary Excretion Kinetics of Nonylphenol in Three Volunteers after a Single Oral Dose

Nonylphenol (NP) is an endocrine-disrupting anthropogenic chemical that is ubiquitous in the environment. Human biomonitoring data and knowledge on internal NP exposure are still sparse, and its human metabolism is largely unknown. Therefore, in this study, we investigated human metabolism and urinary excretion of NP. Three male volunteers received a single oral dose of 1 mg ¹³C₆-labeled NP (10.6-11.7 μg/kg body weight). Consecutive full urine voids were collected for 48 h. A metabolite screening identified nine ring- and/or side chain-oxidized metabolites. We chose the most promising hits, the alkyl chain-oxidized metabolites hydroxy-NP (OH-NP) and oxo-NP, for quantitative investigation next to the parent NP. For this purpose, we newly synthesized specific n - 1-oxidized monoisomeric analytical standards. Quantification of the polyisomeric metabolites was performed via online-solid phase extraction-LC-MS/MS with stable isotope dilution using a previously published consensus method. Alkyl chain hydroxylation (OH-NP) constituted the major metabolism pathway representing 43.7 or 62.2% (depending on the mass transition used for quantification) of the NP dose excreted in urine. The urinary excretion fraction (F_UE) for oxo-NP was 6.0 or 9.3%. The parent NP, quantified via an analogous isomeric ¹³C₆-NP standard, represented 6.6%. All target analytes were excreted predominately as glucuronic acid conjugates. Excretion was rather quick, with concentration maxima in urine 2.3-3.4 h after dosing and biphasic elimination kinetics (elimination half-times first phase: 1.0-1.5 h and second phase: 5.2-6.8 h). Due to its high F_UE and insusceptibility to external contamination (contrary to parent NP), OH-NP represents a robust and sensitive novel exposure biomarker for NP. The novel F_UEs enable to robustly back-calculate the overall NP intakes from urinary metabolite levels in population samples for a well-informed cumulative exposure and risk assessment.

The associations of phthalate biomarkers during pregnancy with later glycemia and lipid profiles

BACKGROUND

Pregnancy induces numerous cardiovascular and metabolic changes. Alterations in these sensitive processes may precipitate long-term post-delivery health consequences. Studies have reported associations between phthalates and metabolic complications of pregnancy, but no study has investigated metabolic outcomes beyond pregnancy.

OBJECTIVES

To examine associations of exposure to phthalates during pregnancy with post-delivery metabolic health.

DESIGN

We quantified 15 urinary phthalate biomarker concentrations during the second and third trimesters among 618 pregnant women from Mexico City. Maternal metabolic health biomarkers included fasting blood measures of glycemia [glucose, insulin, Homeostatic Model Assessment of Insulin Resistance [HOMA-IR], % hemoglobin A1c (HbA1c%)] and lipids (total, high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol, triglycerides), at 4-5 and 6-8 years post-delivery. To estimate the influence of the phthalates mixture, we used Bayesian weighted quantile sum regression and Bayesian kernel machine regression; for individual biomarkers, we used linear mixed models.

RESULTS

As a mixture, higher urinary phthalate biomarker concentrations during pregnancy were associated with post-delivery concentrations of plasma glucose (interquartile range [IQR] difference: 0.13 SD, 95%CrI: 0.05, 0.20), plasma insulin (IQR difference: 0.06 SD, 95%CrI: -0.02, 0.14), HOMA-IR (IQR difference: 0.08 SD, 95% CrI: 0.01, 0.16), and HbA1c% (IQR difference: 0.15 SD, 95%CrI: 0.05, 0.24). Associations were primarily driven by mono-2-ethyl-5-carboxypentyl terephthalate (MECPTP) and the sum of dibutyl phthalate biomarkers (∑DBP). The phthalates mixture was associated with lower HDL (IQR difference: -0.08 SD, 95%CrI: -0.16, -0.01), driven by ∑DBP and monoethyl phthalate (MEP), and higher triglyceride levels (IQR difference: 0.15 SD, 95%CrI: 0.08, 0.22), driven by MECPTP and MEP. The overall mixture was not associated with total cholesterol and LDL. However, ∑DBP and MEP were associated with lower and higher total cholesterol, respectively, and MECPTP and ∑DBP were associated with lower LDL.

CONCLUSIONS

Phthalate exposure during pregnancy is associated with adverse long-term changes in maternal metabolic health. A better understanding of timing of the exact biological changes and their implications on metabolic disease risk is needed.

Substitutes mimic the exposure behaviour of REACH regulated phthalates - A review of the German HBM system on the example of plasticizers

The population is constantly exposed to potentially harmful substances present in the environment, including inter alia food and drinking water, consumer products, and indoor air. Human biomonitoring (HBM) is a valuable tool to determine the integral, internal exposure of the general population, including vulnerable subgroups, to provide the basis for risk assessment and policy advice. The German HBM system comprises of five pillars: (1) the development of suitable analytical methods for new substances of concern, (2) cross-sectional population-representative German Environmental Surveys (GerES), (3) time trend analyses using archived samples from the Environmental Specimen Bank (ESB), (4) the derivation of health-based guidance values as a risk assessment tool, and (5) transfer of data into the European cooperation network HBM4EU. The goal of this paper is to present the complementary elements of the German HBM system and to show its strengths and limitations on the example of plasticizers. Plasticizers have been identified by EU services and HBM4EU partners as priority substances for chemical policy at EU level. Using the complementary elements of the German HBM system, the internal exposure to classical phthalates and novel alternative plasticizers can be reliably monitored. It is shown that market changes, due to regulation of certain phthalates and the rise of substitutes, are rapidly reflected in the internal exposure of the population. It was shown that exposure to DEHP, DiBP, DnBP, and BBzP decreased considerably, whereas exposure to the novel substitutes such as DPHP, DEHTP, and Hexamoll®DINCH has increased significantly. While health-based guidance values for several phthalates (esp. DnBP, DiBP, DEHP) were exceeded quite often at the turn of the millennium, exceedances today have become rarer. Still, also the latest GerES reveals the ubiquitous and concurrent exposures to many plasticizers. Of concern is that the youngest children showed the highest exposures to most of the investigated plasticizers and in some cases their levels of DiBP and DnBP still exceeded health-based guidance values. Over the last years, mixture exposures are increasingly recognized as relevant, especially if the toxicological modes of action are similar. This is supported by a cumulative risk assessment for four endocrine active phthalates which confirms the still concerning cumulative exposure in many young children. Given the adverse health effects of some phthalates and the limited toxicological knowledge of substitutes, exposure reduction and surveillance are needed on German and EU-level. Substitutes need to be monitored, to intervene if exposures are threatening to exceed acceptable levels, or if new toxicological data question their appropriateness. It is strongly recommended to reconsider the use of plastics and plasticizers.

Biomarkers of phthalates and alternative plasticizers in the Flemish Environment and Health Study (FLEHS IV): Time trends and exposure assessment

Restrictions on the use of legacy phthalate esters (PEs) as plasticizer chemicals in several consumer products has led to the increased use of alternative plasticizers (APs), such as di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate (DINCH) and di-(2-ethylhexyl) terephthalate (DEHTP). In the fourth cycle of the Flemish Environment and Health Study (FLEHS IV, 2016-2020), we monitored exposure to seven PEs (diethyl phthalate (DEP), di-(2-ethylhexyl) phthalate (DEHP), di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), butylbenzyl phthalate (BBzP, di-isononyl phthalate (DINP), and di-isodecyl phthalate (DIDP))and three APs (DINCH, DEHTP, and di-(2-ethylhexyl) adipate (DEHA)) by measuring multiple biomarkers in urine of 416 adolescents from Flanders, Belgium (14-15 years old). The reference values show that exposure to PEs is still widespread, although levels of several PE metabolites (e.g., sum of DEHP metabolites, mono-normal-butyl phthalate (MnBP) and mono-benzyl phthalate (MBzP)) have decreased significantly compared to previous human biomonitoring cycles (2003-2018). On the other hand, metabolites of DINCH and DEHTP were detected in practically every participant. Concentrations of AP exposure biomarkers in urine were generally lower than PE metabolites, but calculations of estimated daily intakes (EDIs) showed that exposure to DINCH and DEHTP can be considerable. However, preliminary risk assessment showed that none of the EDI or urinary exposure levels of APs exceeded the available health-based guidance values, while a very low number of participants had levels of MiBP and MnBP exceeding the HBM value. Several significant determinants of exposure could be identified from multiple regression models: the presence of building materials containing PVC, ventilation habits, socio-economic status and season were all associated with PE and AP biomarker levels. Cumulatively, the results of FLEHS IV show that adolescents in Flanders, Belgium, are exposed to a wide range of plasticizer chemicals. Close monitoring over the last decade showed that the exposure levels of restricted PEs have decreased, while newer APs are now frequently detected in humans.

Perinatal Exposure to Phthalates: From Endocrine to Neurodevelopment Effects

Phthalates, as other endocrine disrupting chemicals (EDCs), may alter the homeostasis and the action of hormones and signaling molecules, causing adverse health outcomes. This is true especially for infants, who are both more exposed and sensitive to their effects. Phthalates are particularly harmful when the exposure occurs during certain critical temporal windows of the development, such as the prenatal and the early postnatal phases. Phthalates may also interfere with the neuroendocrine systems (e.g., thyroid hormone signaling or metabolism), causing disruption of neuronal differentiation and maturation, increasing the risk of behavioral and cognitive disorders (ADHD and autistic behaviors, reduced mental, psychomotor, and IQ development, and emotional problems). Despite more studies being needed to better understand the role of these substances, plenty of evidence suggests the impact of phthalates on the neuroendocrine system development and function. This review aims to update the knowledge on the neuroendocrine consequences of neonatal and perinatal exposure to phthalates.

Human metabolism and urinary excretion kinetics of di-n-butyl adipate (DnBA) after oral and dermal administration in three volunteers

Di-n-butyl adipate (DnBA) is used as a plasticizer and in various consumer products (e.g. personal care products) replacing, in part, the endocrine disruptor di-n-butyl phthalate (DnBP). We provide quantitative in vivo data on human DnBA metabolism and excretion after oral dose (105-185 μg/kg bw) and dermal application to three volunteers each as a tool for exposure and risk assessment. Complete and consecutive urine samples were collected for two (oral) and four days (dermal), respectively, and analyzed for the metabolites mono-n-butyl adipate (MnBA), 3- and tentative 4-hydroxy-mono-n-butyl adipate (3OH-MnBA, 4OH-MnBA), and 3-carboxy-mono-n-propyl adipate (3cx-MnPrA), as well as the hydrolysis product adipic acid (AA) using stable isotope dilution quantification. Metabolites were excreted within 24 h after oral dose with one or two concentration maxima at 0.8-3.0 h (n = 3) and 4.8-6.3 h (n = 2). AA was the major but unspecific metabolite with urinary excretion fractions (F_UEs) of 14-26 %. Mean F_UEs (range) of 3cx-MnPrA, MnBA, 3OH-MnBA, and tentative 4OH-MnBA were low, but consistent between volunteers (0.47 % (0.35-0.63 %), 0.079 % (0.065-0.091 %), 0.012 % (0.006-0.016 %), and 0.005 % (0.002-0.009 %), respectively). MnBA and 3OH-MnBA seem to be suitable, specific exposure biomarkers for DnBA, whereas 3cx-MnPrA and 4OH-MnBA seem to originate also from other, unknown sources not related to DnBA. Compared to the oral study, metabolite excretion in the dermal study was delayed and MnBA excretion was somewhat higher compared to the oxidized metabolites. Based on urinary concentrations and the above excretion fractions, calculated uptakes in the dermal study did not exceed the adipate ester ADI of 5 mg/(kg bw*day).

Human biomonitoring in urine samples from the Environmental Specimen Bank reveals a decreasing trend over time in the exposure to the fragrance chemical lysmeral from 2000 to 2018

2-(4-tert-butylbenzyl)propionaldehyde (trade names, e.g. lysmeral or lilial) is a fragrance chemical frequently used in cosmetic products where it is labelled as Butylphenyl methylpropional. A recently developed LC-MS/MS method for the analysis of four lysmeral metabolites (tert-butylbenzoic acid (TBBA), lysmerol, lysmerylic acid, and hydroxy-lysmerylic acid) was applied to 329 urine samples from the Environmental Specimen Bank collected between 2000 and 2018. The two major metabolites TBBA and lysmerol were found in quantifiable concentrations in almost all samples in this study and correlated significantly. Hence, both analytes proved to be specific biomarkers indicating the broad exposure to lysmeral. A significant decline was found for TBBA and lysmerol for the monitored years with the most pronounced decrease from 2012 to 2015. The daily intake (DI) was used to evaluate potential health risks with respect to the derived no-effect level (DNEL) as a threshold for exposure of the general population. The median DI (1.63 μg/kg bw/d) and the 95th percentile (4.69 μg/kg bw/d) corresponded to 2.6% and 7.5% of the lowest DNEL (62.5 μg/kg bw/d for oral administration), respectively. Even though a decreasing trend in exposure was observed the data still calls for efforts to reduce the exposure towards lysmeral since metabolites of lysmeral were detected in nearly all samples and adverse effects cannot be excluded. Clearly, these results need to be substantiated by HBM campaigns in population representative samples like the German Environmental Survey in adults (GerES VI) to provide more robust data for the adult population.

Between- and within-individual variability of urinary phthalate and alternative plasticizer metabolites in spot, morning void and 24-h pooled urine samples

Due to international regulations, commonly used phthalates such as di(2-ethylhexyl) phthalate (DEHP) are being replaced by other phthalates, such as di-isononyl phthalate (DINP), and di-isodecyl phthalate (DIDP) and by alternative plasticizers (APs) with similar chemical characteristics, like di(isononyl)cyclohexane-1,2-dicarboxylate (DINCH), di(2-ethylhexyl) terephthalate (DEHTP), or di-(2-ethylhexyl) adipate (DEHA). Urinary concentrations of metabolites are frequently used in the exposure assessment of non-persistent chemicals and for biomonitoring purposes, the intra- and inter-day variability of the metabolites should be known. However, the short-term variability of AP and several phthalate biomarkers has not been investigated yet. In this study, we collected all spot samples from 10 healthy adults for 5 consecutive days and 24h pooled urine on one additional day to investigate the short-term variability of 22 biomarkers of phthalates and APs. Metabolites of DEP, DEHP, DiBP, DnBP, DBzP, DINP and DIDP were found in high detection frequencies, while metabolites of most APs were found in approximately 50% of the samples. The short-term reproducibility of metabolites with diet as primary source (DEHP, DINP, DIDP) was poor (intraclass correlation coefficient - ICC < 0.4), whereas biomarkers of DEP, DnBP, DiBP and BBzP showed good consistency, most likely due to more continuous sources resulting in less between-day variance. ICC values of AP metabolites were similar to those of DEHP, but more studies are required to confirm these findings. Overall, reproducibility improved considerably when values were corrected for urinary dilution and when only morning voids samples were considered. Levels in morning voids samples were consistent for 5 days and comparable to 24-h pooled urine for all metabolites except for OH-MEHTP, sum DINP and sum DIDP, which supports the use of morning voids in human biomonitoring studies.

Temporal Trends of Exposure to Phthalates and Phthalate Alternatives in California Pregnant Women during 2007-2013: Comparison with Other Populations

Phthalates with potential adverse health effects are being replaced by other phthalates or phthalate alternatives. Little is known about temporal trends of phthalate exposure in pregnant women in the United States. We quantified 16 metabolites of eight phthalates and di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH) in 656 urine samples collected from 192 California pregnant women in 2007-2013 during their second and third trimesters of pregnancy who participated in the MARBLES (Markers of Autism Risk in Babies-Learning Early Signs) study. We used multiple regression to estimate least squares geometric means of phthalate biomarker concentrations and annual percent changes over the study period. Biomarker concentrations of diethyl phthalate (DEP) and three phthalates with known toxicity and adverse health effects (i.e., butyl benzyl phthalate [BBzP], dibutyl phthalate [DBP], di(2-ethylhexyl) phthalate [DEHP]) decreased, while those of di-isobutyl phthalate [DiBP], di-isononyl phthalate [DiNP], and di-n-octyl phthalate [DOP] increased in California pregnant women during our study period. To understand broad social forces that may influence temporal trends and geographic variations in phthalate exposure across countries, we compared our phthalate biomarker concentrations with those of other populations. We observed over a factor of 2 differences in exposure across countries for some phthalate biomarkers and between pregnant and nonpregnant women for DEP.

Temporal trends and determinants of PFR exposure in the Hokkaido Study

The phase-out of polybrominated diphenyl ethers (PBDE) flame retardants has led to the rapid increase of alternatives such as phosphate flame retardants and plasticizers (PFRs) in many consumer products. Exposure to these additive chemicals is widespread and potentially harmful to humans and the environment. In the present study, we assessed the exposure to PFRs through the analysis of metabolites in urine collected from 7-year old children from Hokkaido, Japan between 2012 and 2017. This allowed us to investigate temporal and seasonal trends for PFR metabolite concentrations and to study determinants of exposure. Thirteen metabolites of seven PFRs were measured in morning spot urine samples (n = 400). Multiple regression models were used to quantify the yearly increase in metabolite concentrations per sampling year. Information on the demographics, indoor environment and dietary habits of the participants were derived from self-administered questionnaires. PFR metabolite concentrations were comparable to our previous study of school children (7-12 years old). Eight PFR metabolites were detected in >50% of the samples. During the study time period, concentrations of three metabolites increased significantly: bis(1,3-dichloro-2-propyl) phosphate (BDCIPP; 13.3% per year), 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP; 12.9% per year), and 2-ethylhexyl phenyl phosphate (EHPHP; 6.7% per year). We also found seasonality as a determinant for several PFR metabolites, with 2-fold higher levels in summer for BCIPHIPP and BDCIPP. Concentrations were also significantly impacted by ventilation habits. More frequent window opening or use of mechanical ventilation was consistently associated with higher levels of PFR metabolites in children's urine. This is the first study to show that human exposure to PFRs has increased in recent years in Japan, which indicates that further research into this class of chemicals is warranted.

Time course of phthalate cumulative risks to male developmental health over a 27-year period: Biomonitoring samples of the German Environmental Specimen Bank

In several human biomonitoring surveys, changes in the usage patterns of phthalates have come to light, but their influence on the risks associated with combined exposures is insufficiently understood. Based on the largest study to date, the 27-year survey of urinary phthalate metabolite levels in 24-hour urine samples from the German Environmental Specimen Bank, we present a deep analysis of changing phthalate exposures on mixture risks. This analysis adopts the Hazard Index (HI) approach based on the five phthalates DBP, DIBP, BBP, DEHP and DINP. Calculations of the hazard index for each study participant included updated phthalate reference doses for anti-androgenicity (RfD_AAs) that take account of new evidence of phthalates' developmental toxicity. The Maximum Cumulative Ratio (MCR) approach was used to establish whether a subject's combined exposure was dominated by one phthalate or was influenced by several phthalates simultaneously. Generally, over the years there was a shift towards lower HIs and higher MCRs, reflecting an increased complexity of the combined exposures. The decade from 1988 to about 1999 was characterised by rather high HIs of between 3 and 7 (95th percentile) which were driven by exposure to DBP and DEHP, often exceeding their single acceptable exposures. Traditional single phthalate risk assessments would have underestimated these risks by up to 50%. From 2006 onwards, no study participant experienced exposures above acceptable levels for a single phthalate, but combined exposures were still in excess of HI = 1. From 2011 onwards most individuals stayed below HI = 1. In interpreting these results, we caution against the use of HI = 1 as an acceptable limit and develop proposals for improved and more realistic mixture risk assessments that take account of co-exposures to other anti-androgenic substances also capable of disrupting the male reproductive system. From this perspective, we regard HIs between 0.1 and 0.2 as more appropriate for evaluating combined phthalate exposures. Assessed against lowered HIs of 0.1 - 0.2, the combined phthalate exposures of most study participants exceeded acceptable levels in all study years, including 2015. Continued monitoring efforts for phthalate combinations are required to provide the basis for appropriate risk management measures.

Phthalate metabolites in urine of children and adolescents in Germany. Human biomonitoring results of the German Environmental Survey GerES V, 2014-2017

During the population representative German Environmental Survey of Children and Adolescents (GerES V, 2014-2017) 2256 first-morning void urine samples from 3 to 17 years old children and adolescents were analysed for 21 metabolites of 11 different phthalates (di-methyl phthalate (DMP), di-ethyl phthalate (DEP), butylbenzyl phthalate (BBzP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), di-cyclohexyl phthalate (DCHP), di-n-pentyl phthalate (DnPeP), di-(2-ethylhexyl) phthalate (DEHP), di-iso-nonyl phthalate (DiNP), di-iso-decyl phthalate (DiDP) and di-n-octyl phthalate (DnOP)). Metabolites of DMP, DEP, BBzP, DiBP, DnBP, DEHP, DiNP and DiDP were found in 97%-100% of the participants, DCHP and DnPeP in 6%, and DnOP in none of the urine samples. Geometric means (GM) were highest for metabolites of DiBP (MiBP: 26.1 μg/L), DEP (MEP: 25.8 μg/L), DnBP (MnBP: 20.9 μg/L), and DEHP (cx-MEPP: 11.9 μg/L). For all phthalates but DEP, GMs were consistently higher in the 3-5 years old children than in the 14-17 years old adolescents. For DEHP, the age differences were most pronounced. All detectable phthalate biomarker concentrations were positively associated with the levels of the respective phthalate in house dust. In GerES V we found considerably lower phthalate biomarker levels than in the preceding GerES IV (2003-2006). GMs of biomarker levels in GerES V were only 18% (BBzP), 23% (MnBP), 23% (DEHP), 29% (MiBP) and 57% (DiNP) of those measured a decade earlier in GerES IV. However, some children and adolescents still exceeded health-based guidance values in the current GerES V. 0.38% of the participants had levels of DnBP, 0.08% levels of DEHP and 0.007% levels of DiNP which were higher than the respective health-based guidance values. Accordingly, for these persons an impact on health cannot be excluded with sufficient certainty. The ongoing and substantial exposure of vulnerable children and adolescents to many phthalates confirms the need of a continued monitoring of established phthalates, whether regulated or not, as well as of potential substitutes. With this biomonitoring approach we provide a picture of current individual and cumulative exposure developments and body burdens to phthalates, thus providing support for timely and effective chemicals policies and legislation.

Trends and Patterns of Phthalates and Phthalate Alternatives Exposure in Pregnant Women from Mexico City during 2007-2010

Phthalates are associated with several adverse health outcomes, but few studies have evaluated phthalate exposures in Mexican populations, particularly pregnant women. Between 2007 and 2011, 948 pregnant women from Mexico City were recruited as part of the PROGRESS cohort. We quantified 17 metabolites of phthalates and phthalate alternatives in urine samples collected during the second and third trimesters and examined temporal trends of metabolite concentrations, within-person reproducibility, and relations of individual metabolites with sociodemographic, lifestyle, and occupational factors. Concentrations of mono-2-ethyl-5-carboxypentyl terephthalate, a metabolite of the alternative phthalate di-2-ethylhexyl terephthalate, increased monotonically from 2007 to 2010 (31% per year; 95% confidence interval = 23 and 39%). We observed moderate to high correlations among metabolites collected at the same visit, but there was high variability between second and third trimester phthalate metabolite concentrations (intraclass correlation coefficients = 0.17-0.35). In general, higher socioeconomic status was associated with higher phthalate concentrations. Some metabolites were associated with maternal age and education, but no consistent patterns were observed. Women working in the home and those who worked in administration had higher concentrations of several phthalate metabolites relative to students, professionals, and those in customer service. Biomonitoring efforts are warranted to investigate present and future exposure trends and patterns.