Di-(2-propylheptyl) Phthalate Research Articles

Exposures to Organophosphate Esters and Respiratory Morbidity among School-Aged Children with Asthma.

Organophosphate esters (OPEs) are an emerging class of chemicals used in a variety of consumer products as flame retardants, plasticizers, and additives. While prior epidemiologic studies suggest that OPEs may impact respiratory health, results remain inconclusive. We examined associations between urinary biomarkers of OPEs and symptoms of respiratory morbidity in a panel study of 147 predominantly Black school-aged children with asthma living in Baltimore City, Maryland. The study consisted of up to four seasonal, week-long, in-home visits where urine samples and self-reported asthma symptoms were collected on days 4 and 7 (nsamples = 438). We quantified concentrations of nine urinary OPE biomarkers: bis(2-chloroethyl) phosphate (BCEtp), bis(1-chloro-2-propyl) phosphate (BCPP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), di-n-butyl phosphate (DBuP), di-benzyl phosphate (DBzP), di-o-cresylphosphate (DOCP), di-p-cresylphosphate (DPCP), di-(2-propylheptyl) phthalate (DPHP), and 2,3,4,5-tetrabromo benzoic acid (TBBA). We estimated prevalence odds ratios (POR) of respiratory morbidity symptoms using logistic regression with generalized estimating equations to account for our repeated measure design. We assessed BDCIPP and DPHP as continuous (log2) concentrations and dichotomized exposure of BCEtP, DBuP, and DPCP (detect vs non-detect) based on their lower detection frequencies. We adjusted models for season, visit day, age, gender, caregiver education, health insurance type, exposure to household smoking, atopy, and PM2.5. Higher DPHP concentrations were significantly associated with odds of daytime symptoms (POR: 1.26; 95% CI: 1.04-1.53; p = 0.02) where daytime symptoms consisted of trouble breathing due to asthma, reporting bother caused by asthma, and/or limitation in activities due to asthma. DBuP detection was associated with use of rescue medication on the day of sample collection (POR: 2.36; 95% CI: 1.05-5.29; p = 0.04). We also observed several consistent, albeit non-significant (p > 0.05), positive associations for BCEtP and DPCP and respiratory morbidity measures. This is the first study to evaluate the relationship between OPE biomarkers and respiratory morbidity symptoms in children with asthma, and findings suggest that further studies are warranted to confirm whether these associations are causal.

Development, testing, parameterisation, and calibration of a human PBK model for the plasticiser, di (2-ethylhexyl) adipate (DEHA) using in silico, in vitro and human biomonitoring data.

Introduction: A physiologically based biokinetic model for di (2-ethylhexyl) adipate (DEHA) based on a refined model for di-(2-propylheptyl) phthalate (DPHP) was developed to interpret the metabolism and biokinetics of DEHA following a single oral dosage of 50mg to two male and two female volunteers. Methods: The model was parameterized using in vitro and in silico methods such as, measured intrinsic hepatic clearance scaled from in vitro to in vivo and algorithmically predicted parameters such as plasma unbound fraction and tissue:blood partition coefficients (PCs). Calibration of the DEHA model was achieved using concentrations of specific downstream metabolites of DEHA excreted in urine. The total fractions of ingested DEHA eliminated as specific metabolites were estimated and were sufficient for interpreting the human biomonitoring data. Results: The specific metabolites of DEHA, mono-2-ethyl-5-hydroxyhexyl adipate (5OH-MEHA), mono-2-ethyl-5-oxohexyl adipate (5oxo-MEHA), mono-5-carboxy-2-ethylpentyl adipate (5cx-MEPA) only accounted for ∼0.45% of the ingested DEHA. Importantly, the measurements of adipic acid, a non-specific metabolite of DEHA, proved to be important in model calibration. Discussion: The very prominent trends in the urinary excretion of the metabolites, 5cx-MEPA and 5OH-MEHA allowed the important absorption mechanisms of DEHA to be modelled. The model should be useful for the study of exposure to DEHA of the general human population.

Development, testing, parameterisation, and calibration of a human PBPK model for the plasticiser, di-(2-ethylhexyl) terephthalate (DEHTP) using in silico, in vitro and human biomonitoring data.

A physiologically based pharmacokinetic model for di-(2-ethylhexyl) terephthalate (DEHTP) based on a refined model for di-(2-propylheptyl) phthalate (DPHP) was developed to interpret the metabolism and biokinetics of DEHTP following a single oral dose of 50mg to three male volunteers. In vitro and in silico methods were used to generate parameters for the model. For example, measured intrinsic hepatic clearance scaled from in vitro to in vivo and plasma unbound fraction and tissue:blood partition coefficients (PCs) were predicted algorithmically. Whereas the development and calibration of the DPHP model was based upon two data streams, blood concentrations of parent chemical and first metabolite and the urinary excretion of metabolites, the model for DEHTP was calibrated against a single data stream, the urinary excretion of metabolites. Despite the model form and structure being identical significant quantitative differences in lymphatic uptake between the models were observed. In contrast to DPHP the fraction of ingested DEHTP entering lymphatic circulation was much greater and of a similar magnitude to that entering the liver with evidence for the dual uptake mechanisms discernible in the urinary excretion data. Further, the absolute amounts absorbed by the study participants, were much higher for DEHTP relative to DPHP. The in silico algorithm for predicting protein binding performed poorly with an error of more than two orders of magnitude. The extent of plasma protein binding has important implications for the persistence of parent chemical in venous blood-inferences on the behaviour of this class of highly lipophilic chemicals, based on calculations of chemical properties, should be made with extreme caution. Attempting read across for this class of highly lipophilic chemicals should be undertaken with caution since basic adjustments to PCs and metabolism parameters would be insufficient, even when the structure of the model itself is appropriate. Therefore, validation of a model parameterized entirely with in vitro and in silico derived parameters would need to be calibrated against several human biomonitoring data streams to constitute a data rich source chemical to afford confidence for future evaluations of other similar chemicals using the read-across approach.

Refinement and calibration of a human PBPK model for the plasticiser, Di-(2-propylheptyl) phthalate (DPHP) using in silico, in vitro and human biomonitoring data.

An existing physiologically based pharmacokinetic model for Di-(2-propylheptyl) phthalate (DPHP) was refined to improve the simulations of the venous blood concentrations of the primary monoester metabolite, mono-(2-propylheptyl) phthalate (MPHP). This was considered a significant deficiency that should be addressed because the primary metabolite of other high molecular weight phthalates has been associated with toxicity. The various processes that influence the concentration of DPHP and MPHP in blood were re-evaluated and modified. A few simplifications of the existing model were made, including the removal of enterohepatic recirculation (EHR) of MPHP. However, the primary development was describing the partial binding of MPHP to plasma proteins following uptake of DPHP and metabolism in the gut affording better simulation of the trends observed in the biological monitoring data. Secondly, the relationship between blood concentrations and the urinary excretion of secondary metabolites was explored further because the availability of two data streams provides a better understanding of the kinetics than reliance on just one. Most human studies are conducted with few volunteers and generally with the absence of blood metabolite measurements which would likely imply an incomplete understanding of the kinetics. This has important implications for the "read across" approach proposed as part of the development of New Approach Methods for the replacement of animals in chemical safety assessments. This is where the endpoint of a target chemical is predicted by using data for the same endpoint from another more "data rich" source chemical. Validation of a model parameterized entirely with in vitro and in silico derived parameters and calibrated against several data streams would constitute a data rich source chemical and afford more confidence for future evaluations of other similar chemicals using the read-across approach.

Diverging trends of plasticizers (phthalates and non-phthalates) in indoor and freshwater environments—why?

BackgroundEuropean chemicals management aims to protect human health and the environment from legacy and emerging contaminants. The plasticizer market changed in response to the restriction of low molecular weight (LMW) phthalate plasticizers such as Di (2-ethylhexyl) phthalate (DEHP) due to their hazardous properties. We investigated patterns and trends of 19 regulated and emerging plasticizers in house dust from German homes and in suspended particulate matter (SPM) from major German rivers. The samples were used from the mid-2000s and late 2010s from two governmental long-term monitoring programs in Germany.ResultsWhile the sum of the respective plasticizer levels hardly changed over the study period, we observed a significant decrease of LMW phthalates in both house dust (2003/06, 80% of the ∑plasticizer concentration; 2014/17, 31%) and SPM (2005, 48%; 2017, 28%). This was accompanied by their substitution with high molecular weight (HMW) phthalates and non-phthalates. HMW phthalates increased from 19% of the ∑plasticizer concentration to 46% between the mid-2000s and the late 2010s in house dust, and from 50% to 63% in SPM samples. Diisononyl phthalate (DINP) replaced DEHP as the dominant plasticizer in both compartments. A significant tenfold increase (p < 0.05) was observed in SPM samples for Di (2-propylheptyl) phthalate (DPHP) (1–13%), compared to low levels in house dust (2014/17, 1%). Non-phthalates increased to 23% of the ∑plasticizer concentration in house dust but only to 9% in SPM (mid-2000s: house dust, < 1%; SPM, 1.5%). In recent house dust samples, Di (2-ethylhexyl) terephthalate (DEHT) had the third highest concentration of all plasticizers and contributed 18% to the total load, whereas Tris (2-ethylhexyl) trimellitate (TOTM) was one of the major non-phthalates in SPM samples.ConclusionsUnlike in the indoor environment, the substitution of LMW phthalates in the aquatic environment was characterized by a significant shift towards plasticizers with potentially hazardous properties. DPHP and TOTM were identified by European chemical regulation as potentially endocrine disrupting compounds and persistent, bioaccumulative and toxic compounds. Our data document the need for integrated chemicals management to safeguard the transition to a non-toxic environment.

Phthalate levels in prenatal and postnatal bedroom dust in the SELMA study

Phthalates are common in polyvinyl chloride (PVC) plastics and numerous consumer goods in our homes from which they can migrate and adhere to indoor dust particles. It is known that indoor dust exposure contribute to human phthalate intake; however, there is a lack of large studies with a repeated-measure design investigating how phthalate levels in indoor dust may vary over time in people's homes.This study investigated levels of seven phthalates and one alternative plasticiser di-iso-nonyl-cyclohexane-di-carboxylate (DiNCH) in bedroom dust collected prenatally around week 25 during pregnancy and postnatally at six months after birth, from 496 Swedish homes. Prenatal and postnatal phthalate levels were compared using correlation and season-adjusted general linear regression models.Over the nine-month period, levels of six out of seven phthalates were associated as indicated by a positive Pearson correlation (0.18 < r < 0.50, P < .001) and Lin's concordance correlation between matched prenatal and postnatal dust samples. Compared to prenatal levels, the season-adjusted postnatal levels decreased for five phthalates, whilst di-ethyl-hexyl phthalate (DEHP), di-2-propylheptyl phthalate (DPHP) and DiNCH increased.The results suggest that families with higher phthalate levels in bedroom dust during pregnancy are likely to remain among those with higher levels in the infancy period. However, all average phthalate levels changed over this specific nine-month period suggesting that available phthalate sources or their use were altered between the dust collections. Changes in home characteristics, family lifestyle, and phthalate replacement trends may contribute to explain the differences.

Variability and predictors of urinary organophosphate ester concentrations among school-aged children

Organophosphate esters (OPE) are flame retardants and plasticizers used in a wide range of consumer products. Despite their widespread use, few studies have characterized pediatric exposures. We assessed variability and predictors of OPE exposures in a cohort panel study of 179 predominantly Black school-aged children with asthma in Baltimore City, MD. The study design included up to four seasonal week-long in-home study visits with urine sample collection on days 4 and 7 of each visit (nsamples = 618). We quantified concentrations of 9 urinary OPE biomarkers: bis(2-chloroethyl) phosphate (BCEtp), bis(1-chloro-2-propyl) phosphate, bis(1,3-dichloro-2-propyl) phosphate (BDCPP), di-benzyl phosphate (DBuP), di-benzyl phosphate, di-o-cresylphosphate, di-p-cresylphosphate (DPCP), di-(2-propylheptyl) phthalate (DPHP), 2,3,4,5-tetrabromo benzoic acid. We assessed potential predictors of exposure, including demographic factors, household characteristics, and cleaning behaviors. We calculated Spearman/tetrachoric correlations and intraclass correlation coefficients (ICCs) to examine within-week and seasonal intra-individual variability, respectively. We assessed OPE predictors using linear models for continuous log2 concentrations (BDCPP and DPHP) and logistic models for odds of detection (BCEtP, DBuP, DPCP), with generalized estimating equations to account for repeated measures. For all OPEs, we observed moderate within-week correlations (rs: 0.31–0.63) and weak to moderate seasonal reliability (ICC: 0.18–0.38). BDCPP and DPHP concentrations were higher in the summer compared to other seasons. DPHP concentrations were lower among males than females (%diff: −53.5%; 95% CI: −62.7, −42.0) and among participants spending >12 h/day indoors compared to ≤12 h (%diff: −20.7%; 95% CI: −32.2, −7.3). BDCPP concentrations were lower among children aged 8–10 years compared to 5–7 years (%diff: −39.1%; 95% CI: −55.9, −15.9) and higher among children riding in a vehicle on the day of sample collection compared to those who had not (%diff: 28.5%; 95% CI: 3.4, 59.8). This study is the first to characterize within-week and seasonal variability and identify predictors of OPE biomarkers among Black school-aged children, a historically understudied population.

The Xenopus laevis teratogenesis assay for developmental toxicity of phthalate plasticizers and alternatives

Contamination of phthalate ester plasticizers threatens the wildlife as well as human health. To evaluate the developmental toxicity of commonly used phthalate esters and emerging alternatives, the frog embryo teratogenesis assay-Xenopus (FETAX) was conducted for dibutyl-phthalate (DBP), benzyl-butyl-phthalate (BBP), dioctyl-terephthalate (DOTP), di(2-propylheptyl)-phthalate (DPHP), diisononyl-phthalate (DINP), diisodecyl-phthalate (DIDP), diethyl hexyl cyclohexane (DEHCH), and diisononyl-cyclohexane-1,2-dicarboxylate (DINCH). The 96-hrs LC50 for DBP, BBP, DOTP, DIDP, DINCH, DINP, DPHP, and DEHCH were 18.3, 20.1, 588.7, 718.0, 837.5, 859.3, 899.0, and 899.0 mg/L, respectively. The 96-hrs EC50 of developmental abnormality of DBP, BBP, DPHP, DOTP, DINP, DEHCH, DINCH, and DIDP were 7.5, 18.2, 645.1, 653.6, 664.4, 745.6, 813.7, and 944.5 mg/L, respectively. The lowest observed effective concentration for embryonic survival, malformation, and growth was DINP, DBP, BBP, DIDP, DPHP, DINCH, DEHCH, and DOTP in increasing order. In tadpoles, DBP, BBP, DEHCH, DINP, and DIDP caused inositol-requiring enzyme 1 or protein kinase R-like endoplasmic reticulum kinase pathway endoplasmic reticulum stress (ERS) in order, and BBP, DBP, DOTP, DPHP, DINP, and DIDP caused long term ERS-related apoptosis or mitochondrial apoptosis in order. Together, in Xenopus embryos, the developmental toxicity and the cellular stress-inducing potential of tested plasticizers were DEHCH, DINCH, DPHP, DIDP, DINP, DOTP, BBP, and DBP in increasing order. In consideration of public as well as environmental health this information would be helpful for industrial choice of phthalate ester plasticizers and their alternatives.

DNA oxidative damage in pregnant women upon exposure to conventional and alternative phthalates.

Exposure to alternative phthalates and related health effects in pregnant women are rarely reported. Nineteen phthalate metabolites and a DNA oxidative damage biomarker 8-hydroxy-2'-deoxyguanosine (8-OHdG) were determined in urine samples of pregnant women recruited in South China. The detection frequencies and concentration of selected alternative phthalates, i.e., diisononyl phthalate (DiNP), diisodecyl phthalate (DiDP) and di-(2-propylheptyl) phthalate (DPHP) were lower than those of conventional phthalates. However, mono-(6-hydroxy-2-propylheptyl) phthalate, a metabolite of DPHP, was detected in 70% of urine samples (median: 0.13ng/mL). The estimated daily intakes of conventional plasticizers, including dimethyl phthalate, di-n-butyl phthalate, diisobutyl phthalate and di-(2-ethylhexyl) phthalate (median range: 1.0-3.0μg/kg_bw/day) were significantly higher than those of DiNP (0.08μg/kg_bw/day) and DPHP (0.03μg/kg_bw/day) (p<0.05). Approximately 24% of pregnant women were at high risk when cumulative risk from exposure to several phthalates was considered. The concentrations of phthalate metabolites and urinary 8-OHdG were significantly correlated with each other (r=0.206-0.772, p<0.01), which were further conformed by multiple linear regression analysis (β=0.168-0.639, p<0.01). In addition, conventional phthalates were more strongly correlated with 8-OHdG than alternative phthalates (i.e., DiNP, DPHP), partly suggesting the relatively smaller health effects of alternatives due to their low exposure doses and toxicities. These findings suggested that alternative phthalates have entered the human body from consumer products in the study area, and exposure-related risk of DNA oxidative stress was comparatively lower.

An integrated exposure and pharmacokinetic modeling framework for assessing population-scale risks of phthalates and their substitutes.

To effectively incorporate in vitro-in silico-based methods into the regulation of consumer product safety, a quantitative connection between product phthalate concentrations and in vitro bioactivity data must be established for the general population. We developed, evaluated, and demonstrated a modeling framework that integrates exposure and pharmacokinetic models to convert product phthalate concentrations into population-scale risks for phthalates and their substitutes. A probabilistic exposure model was developed to generate the distribution of multi-route exposures based on product phthalate concentrations, chemical properties, and human activities. Pharmacokinetic models were developed to simulate population toxicokinetics using Bayesian analysis via the Markov chain Monte Carlo method. Both exposure and pharmacokinetic models demonstrated good predictive capability when compared with worldwide studies. The distributions of exposures and pharmacokinetics were integrated to predict the population distributions of internal dosimetry. The predicted distributions showed reasonable agreement with the U.S. biomonitoring surveys of urinary metabolites. The "source-to-outcome" local sensitivity analysis revealed that food contact materials had the greatest impact on body burden for di(2-ethylhexyl) adipate (DEHA), di-2-ethylhexyl phthalate (DEHP), di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), and di(2-propylheptyl) phthalate (DPHP), whereas the body burden of diethyl phthalate (DEP) was most sensitive to the concentration in personal care products. The upper bounds of predicted plasma concentrations showed no overlap with ToxCast in vitro bioactivity values. Compared with the in vitro-to-in vivo extrapolation (IVIVE) approach, the integrated modeling framework has significant advantages in mapping product phthalate concentrations to multi-route risks, and thus is of great significance for regulatory use with a relatively low input requirement. Further integration with new approach methodologies will facilitate these in vitro-in silico-based risk assessments for a broad range of products containing an equally broad range of chemicals.

Development, Testing, Parameterisation and Calibration of a Human PBPK Model for the Plasticiser, Di-(2-propylheptyl) Phthalate (DPHP) Using in Silico, in vitro and Human Biomonitoring Data.

A physiologically based pharmacokinetic model for Di-(2-propylheptyl) phthalate (DPHP) was developed to interpret the biokinetics in humans after single oral doses. The model was parameterized with in vitro and in silico derived parameters and uncertainty and sensitivity analysis was used during the model development process to assess structure, biological plausibility and behaviour prior to simulation and analysis of human biological monitoring data. To provide possible explanations for some of the counter-intuitive behaviour of the biological monitoring data the model included a simple lymphatic uptake process for DPHP and enterohepatic recirculation (EHR) for DPHP and the mono ester metabolite mono-(2-propylheptyl) phthalate (MPHP). The model was used to simultaneously simulate the concentration-time profiles of blood DPHP, MPHP and the urinary excretion of two metabolites, mono-(2-propyl-6-hydroxyheptyl) phthalate (OH-MPHP) and mono-(2-propyl-6-carboxyhexyl) phthalate (cx-MPHP). The availability of blood and urine measurements permitted a more robust qualitative and quantitative investigation of the importance of EHR and lymphatic uptake. Satisfactory prediction of blood DPHP and urinary metabolites was obtained whereas blood MPHP was less satisfactory. However, the delayed peak of DPHP concentration relative to MPHP in blood and second order metabolites in urine could be explained as a result of three processes: 1) DPHP entering the systemic circulation from the lymph, 2) rapid and very high protein binding and 3) the efficiency of the liver in removing DPHP absorbed via the hepatic route. The use of sensitivity analysis is considered important in the evaluation of uncertainty around in vitro and in silico derived parameters. By quantifying their impact on model output sufficient confidence in the use of a model should be afforded. This approach could expand the use of PBPK models since parameterization with in silico techniques allows for rapid model development. This in turn could assist in reducing the use of animals in toxicological evaluations by enhancing the utility of “read across” techniques.

Prenatal phthalate exposure and early childhood wheeze in the SELMA study.

Prenatal maternal phthalate exposure has been associated with wheeze and asthma in children, but results are inconclusive. Previous studies typically assessed exposure in late pregnancy, included only a small number of old phthalates, and assessed outcomes in children aged 5 years or older. We explored associations between 1st trimester prenatal maternal exposure to a wider range of phthalates and wheeze in early childhood. First trimester concentrations of 14 metabolites from 8 phthalates and one alternative plasticizer were quantified in first-morning void urine from 1148 mothers in the Swedish SELMA study. Associations between log-transformed metabolite concentrations and parental reported ever wheeze among 24-month-old children were investigated with logistic regression models adjusted for parental asthma/rhinitis, sex of child, maternal education, smoking, and creatinine. Metabolites of replacement phthalates di-iso-decyl phthalate (DiDP) and di-2-propylheptyl phthalate (DPHP) were associated with increased risk for wheeze (aOR 1.47, 95% CI 1.08-2.01 and aOR 1.49, 95% CI 1.04-2.15, respectively). The associations with DiDP and DPHP were stronger among children whose parents did not have asthma or rhinitis. In this group, wheeze was also associated with metabolites of butyl-benzyl phthalate (BBzP) and di-iso-nonyl phthalate (DiNP). Maternal phthalate exposure during early pregnancy may be a risk factor for wheeze in early childhood, especially among children whose parents do not have asthma or rhinitis symptoms.

Exposure to organophosphate esters, phthalates, and alternative plasticizers in association with uterine fibroids

Exposure to endocrine disrupting chemicals is suggested to be responsible for the development or progression of uterine fibroids. However, little is known about risks related to emerging chemicals, such as organophosphate esters (OPEs) and alternative plasticizers (APs). A case-control study was conducted to investigate whether exposures to OPEs, APs, and phthalates, were associated with uterine fibroids in women of reproductive age. For this purpose, the cases (n = 32) and the matching controls (n = 79) were chosen based on the results of gynecologic ultrasonography among premenopausal adult women in Korea and measured for metabolites of several OPEs, APs, and major phthalates. Logistic regression models were employed to assess the associations between chemical exposure and disease status. Factor analysis was conducted for multiple chemical exposure assessments as a secondary analysis. Among OPE metabolites, diphenyl phosphate (DPHP), 2-ethylhexyl phenyl phosphate (EHPHP), and 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP) were detected in >80% of the subjects. Among APs, metabolites of di-isononyl phthalate (DINP) and di(2-propylheptyl) phthalate (DPrHpP) were detected in >75% of the urine samples. The odds ratios (ORs) of uterine fibroids were significantly higher among the women with higher exposures to tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris(2-butoxyethyl) phosphate (TBOEP), di(2-ethylhexyl) terephthalate (DEHTP), DPrHpP, and di-(iso-nonyl)-cyclohexane-1,2-dicarboxylate (DINCH). In addition, urinary concentrations of mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), a sum of five di(2-ethylhexyl) phthalate metabolites (∑5DEHP), and mono(4-methyl-7-hydroxyoctyl) phthalate (OH-MINP) were significantly higher in the cases. In factor analysis, a factor heavily loaded with DPrHpP and DEHP was significantly associated with uterine fibroids, supporting the observation from the single chemical regression model. We found for the first time that several metabolites of OPEs and APs are associated with increased risks of uterine fibroids among pre-menopausal women. Further epidemiological and mechanistic studies are warranted to validate the associations observed in the present study.

Non-occupational exposure to phthalates in Finland

The aim of this study was to assess phthalate exposure of non-occupationally exposed working aged population in Finland. Studied phthalates included diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), benzyl butyl phthalate (BzBP), dicyclohexyl phthalate (DCHP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), diisodecyl phthalate (DiDP), di(2-propylheptyl) phthalate (DPHP), and di-n-octyl phthalate (DnOP). Sample collection campaign took place in 2015.Metabolites of DEP, DnBP and DiBP were detected in all the first morning void urine samples of the non-occupationally exposed volunteers (n = 60; 42 women and 18 men; aged 25–63). Metabolite of BBP and secondary metabolites of DEHP and DiNP were detected in >90% of the samples. MCHP (1.7%), MEHP (18.3%), cx-MiNP (8.3%) and MnOP (1.7%) were less frequently detected. MiNP and OH-MPHP were not detected in any of the urine samples.The observed levels were mostly comparable to the levels published in the adult population in Europe and the US. One notable difference was the observed higher exposure of the Finnish study population to DnBP in comparison to the German, Austrian, Norwegian and US populations. The levels of individual phthalates did not often correlate very well with each other. In most cases, higher exposure to phthalates was seen in females in comparison to males, which is in accordance with other studies.The urinary levels were compared to the biomonitoring equivalents (BEs), which were calculated on the basis of published DNELs (derived no-effect levels). The P95 levels of individual phthalates remained below the respective BEs, the highest risk characterization ratio (RCR) being 0.88 for DnBP and the second highest 0.34 for DiBP. For other phthalates, the RCRs were below 0.2. Using the P95 levels, combined exposure to DnBP, DiBP, DEHP and BBP resulted in risk characterization ratio exceeding 1. This suggests a need to limit the exposure to these phthalates.

Occupational Exposure of Plastics Workers to Diisononyl Phthalate (DiNP) and Di(2-propylheptyl) Phthalate (DPHP) in Finland.

The aim of this study was to assess occupational exposure to diisononyl phthalate (DiNP) and di(2-propylheptyl) phthalate (DPHP] in Finland. Four companies took part in the research project: A cable factory, a plastic producing company, a producer of coated textiles, and a tarpaulin producer. The cable factory used DPHP (and occasionally also diisodecyl phthalate, DiDP), the plastic producing company used both DPHP and DiNP, and the latter two companies used DiNP in their production. Exposure was assessed by measuring phthalate metabolites in urine samples (biomonitoring) and by performing air measurements. Low-level occupational exposure to DiNP was observed in the company that produced coated textiles—out of eight workers, one extruder operator was exposed to DiNP at levels exceeding the non-occupationally exposed population background levels. Some workers in the cable factory and the plastics producing company were occupationally exposed to DPHP. Air levels of phthalates were generally low, mostly below the limit of quantification. All phthalate metabolite concentrations were, however, well below the calculated biomonitoring equivalents, which suggests that the health risks related to the exposure are low.

Trends for plasticizers in German freshwater environments – Evidence for the substitution of DEHP with emerging phthalate and non-phthalate alternatives

Plasticizers are marketed in high volumes and Di(2-ethylhexyl) phthalate (DEHP) is frequently detected in the environment and human populations. Industry had largely relied on DEHP until regulation started to restrict its marketing in 1999 due to environmental and human health concerns. The aim of this study was to obtain spatial-temporal trends for DEHP and its substitutes in German rivers. We have investigated suspended particulate matter (SPM) samples from the German Environmental Specimen Bank (ESB) for the presence of 23 plasticizers, i.e. 17 phthalates and 6 non-phthalates. The samples were collected in the last 10 years at 13 sites in large river basins in Germany such as the Rhine, Elbe and Danube. A decrease in DEHP concentrations was observed at all sampling sites between the mid-2000s and 2017. The maximum concentration for DEHP was determined in 2006 in samples from Rehlingen/Saar (6720 ng/g dry weight (dw)). By 2017, the DEHP concentration in Rehlingen had dropped to 2080 ng/g dw. Currently, Diisononyl phthalate (DINP) is the plasticizer with the highest levels in the SPM samples (maximum value 4150 ng/g dw in Rehlingen/Saar). Our results show that novel plasticizers such as Diisononylcyclohexane-1,2-dicarboxylate (DINCH) spread rapidly in surface waters after their market introduction. We have found several plasticizers of emerging concern in the environmental samples, the further use of which is currently under review under the EU chemicals regulation (REACH, registration, evaluation, authorisation and restriction of chemicals). In particular for Di(2-propylheptyl) phthalate (DPHP) a significant increase in concentration was observed at almost all sites between the mid-2000s and 2017, for example in Prossen/Elbe from 24 ng/g dw (2005) to 1380 ng/g dw (2017).

Occurrence and human health risks of phthalates in indoor air of laboratories

Phthalate acid esters (PAEs) are of serious concern as a human health risk due to their ubiquitous presence in indoor air. In the present study, fifteen PAEs in the indoor air samples from physical, chemical, and biological laboratories in Guangzhou, southern China were analysed using gas chromatography mass spectrometry. Extremely high levels of PAEs of up to 6.39 × 104 ng/m3 were detected in some laboratories. Diisobutyl phthalate (DiBP), di(methoxyethyl) phthalate (DMEP), and di-n-butyl phthalate (DBP) were the dominant PAEs with median levels of 0.48 × 103, 0.44 × 103, and 0.39 × 103 ng/m3, respectively, followed by di-(2-propylheptyl) phthalate (DPHP) and di(2-ethylhexyl) phthlate (DEHP) (median levels: 0.16 × 103 and 0.13 × 103 ng/m3, respectively). DMEP and DPHP were found for the first time in indoor air. Principal component analysis indicated that profiles of PAEs varied greatly among laboratory types, suggesting notable variations in sources. The results of independent samples t-tests showed that levels of PAEs were significantly influenced by various environmental conditions. Both the non-carcinogenic and carcinogenic health risks from human exposure to PAEs based on the daily exposure dose in laboratory air were acceptable. Further research should be conducted to investigate the long-term health effects of exposure to PAEs in laboratories.

Phthalate exposure in pregnant women with systemic lupus erythematous (SLE)

TPS 632: Health effects of flame retardants and plasticizers, Johan Friso Foyer, Floor 1, August 27, 2019, 3:00 PM - 4:30 PM Background: Environmental chemicals might contribute to the pathogenesis of autoimmune diseases in combination with established genetic factors. Phthalate exposure in pregnant women may influence fetal growth and birth outcomes. Hence, we assessed phthalate exposure in pregnant women with systemic lupus erythematous (SLE) and compared levels with nationally-representative and pregnant populations. Methods: Participants were 50 pregnant women from the New York City (NYC) sample of PROMISSE (2003-2010), a multi-ethnic/racial cohort designed to prospectively assess adverse pregnancy outcomes in SLE women with inactive or mild/moderate disease activity. We measured urinary concentrations of 21 phthalate metabolites during each trimester and compared median concentrations with 1) 15-to-50 year-old women in the National Health and Nutrition Examination Survey (NHANES) 2003-2010; and 2) a contemporary population-based cohort of pregnant women in NYC (n=240). Results: Intraclass correlations for three measurements across pregnancy varied between r=0 [mono-carboxy isooctyl phthalate (mCIOP)] and r=0.57 [mono-n-butyl-phthalate (mBP)]. Mono-(3-carboxypropyl) phthalate (mCPP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (mEHHP), mono-(2-ethyl-5-carboxypentyl) phthalate (mECPP), mono-(2-ethyl-5-oxohexyl) phthalate (mEOHP), mCIOP, and mono-carboxy isononyl phthalate (mCINP) were detected in all pregnant women, comparable to NHANES. Metabolites of di-(2-propylheptyl) phthalate (DPHP) and 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH) were detected in 4-55% of participant. Compared to NHANES, pregnant women with SLE had higher first trimester concentration of mono-(2-ethylhexyl) phthalate (MEHP) [median=3.9 ng/mL interquartile range (IQR)=6.0 vs 2.5 ng/mL, IQR=5.45], mono-isobutyl phthalate (mIBP) (median=12.8 vs 7.6 ng/mL), mono-isononyl phthalate (mINP) (median=2.7 vs. 0.87 ng/mL), and mCIOP (median=14.9 vs 6.9 ng/mL). Concentrations of other phthalate metabolites were comparable between groups. Pregnant women with SLE had higher phthalate levels than the NYC cohort. Conclusions: Pregnant women with SLE had higher concentrations of certain phthalate metabolites than controls. This cross-sectional analysis cannot rule out that SLE might influence phthalate metabolism. Sociodemographic and lifestyles factors might also explain the results; therefore, further investigation is needed.

Using a high-resolution mass spectrometry-based metabolomics strategy for comprehensively screening and identifying biomarkers of phthalate exposure: Method development and application

Di-(2-propylheptyl) phthalate (DPHP) is an alternative plasticizer that can replace other phthalates currently being scrutinized, and its use and production volumes are increasing. This study aimed to develop a high-resolution mass spectrometry (HRMS)-based metabolomics strategy to comprehensively screen urinary biomarkers of DPHP exposure and filter out potentially useful DPHP exposure markers for human exposure assessments. This strategy included three stages: screening of biomarkers, verification of dose-response relationships in laboratory animals, and application in human subjects. The multivariate data analysis method known as orthogonal partial least-squares discriminant analysis (OPLS-DA) was used to screen and find meaningful signals in an MS dataset generated from urine samples collected from DPHP-administered rats. Thirty-six MS signals were verified as exposure marker candidates by assessing dose-response relationships in an animal feeding study. A biotransformation product of DPHP, mono-(2-propyl-7-dihydroxy-heptyl) phthalate, was suggested as a DPHP exposure marker for general human exposure assessments after the human application study and chemical structure identification. Three previously oxidized DPHP biotransformation products might be suitable for human exposure assessments in high-level exposure groups but not in the general population due to their low sensitivity.

Internal exposure of young German adults to di(2-propylheptyl) phthalate (DPHP): Trends in 24-h urine samples from the German Environmental Specimen Bank 1999-2017.

Di(2-propylheptyl) phthalate (DPHP) is used as a substitute for high molecular weight phthalates like di(2-ethylhexyl) phthalate (DEHP) which were subjected to authorization under REACh in 2015. An earlier study on the time trend of exposure in human 24-h urine samples from the German Environmental Specimen Bank has revealed that metabolites of DPHP emerged in 2009 and 2012 (Schütze et al., 2015). In order to better assess a potential trend and the present state of exposure to DPHP, we now measured 180 urine samples from the German Environmental Specimen Bank, 60 per year, collected in 2011, 2014 and 2017, randomized and blinded before analysis. Together with the previously analyzed samples, data for a total of 480 samples covering 19 years from 1999 to 2017 was thus generated. We were able to show that DPHP exposure of the studied population, university students from Münster (Northwestern Germany), has remained essentially constant since 2011, after a rapid increase starting around 2009. Even so, urinary metabolite concentrations were always in the low ppb or sub-ppb range, indicating that DPHP exposure of the general population is substantially lower than for other modern plasticizers, and far below levels currently regarded as critical. DPHP is a plasticizer which is mostly used in non-sensitive applications with little probability of close contact to humans. Still, we observed how temporal trends of DPHP exposure largely follow trends of DPHP consumption in the Western European market. Our results hence demonstrate the potential of biomonitoring to sensitively detect the effects of industrial product strategy on the environment, even when biomarkers are present only at trace level.