Human biomonitoring of phthalate exposure in Austrian children and adults and cumulative risk assessment

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.

Endocrine disrupting chemicals in children's and their parents' urine: Is the exposure related to the Chinese and Western lifestyle?

Children are known to be more vulnerable to exposure to endocrine-disrupting chemicals (EDCs) compared to adults, but evaluating the exposure pathways can be challenging. This research employed target and non-target analysis (NTA) to examine the exposure characteristics of EDCs in spot urine samples collected from 46 children's (aged 3-12 years) and their parents in Hong Kong (Chinese/Western lifestyle) and Guangzhou (mainly Chinese lifestyle). The results revealed that the geometric mean concentrations of phthalate esters metabolites (mPAEs) and bisphenols (BPs) in children's urine were 127.3 μg/gcrea and 2.5 μg/gcrea in Guangzhou, and 93.7 μg/gcrea and 2.9 μg/gcrea in Hong Kong, respectively, which were consistent with global levels. NTA identified a total of 1069 compounds, including 106 EDCs, commonly detected in food, cosmetics, and drugs. Notable regional differences were observed between Guangzhou and Hong Kong with potential sources of EDCs including dietary and cosmetic additives, toys, flooring and dust, as well as differences in lifestyles, diet, and living environment. However, age was found to significantly impact EDC exposure. The quantified EDCs (mPAEs and BPs) posed possible health risks to 60% of the children. Moreover, the presence of caffeine in children's urine, which exhibited higher detection rates in children from Hong Kong (95.6%) and Guangzhou (44.4%), warrants further attention. The sources of EDCs exposure in these regions need to be fully confirmed.

Concentrations of bisphenols and phthalate esters in the muscle of Mediterranean striped dolphins (Stenella coeruleoalba)

Bisphenols (BPs) and phthalate esters (PAEs) are important compounds for the plastics industry, also called "everywhere chemicals" due to their ubiquity in daily use products. Both chemical groups are well-known environmental contaminants, whose presence has been reported in all environmental compartments, and whose effects, mainly associated to endocrine disruption, are detrimental to living organisms. Cetaceans, due to their long life-span, low reproduction rate and high position in the trophic web, are especially vulnerable to the effects of contaminants. However, little is known about BP and PAE concentrations in cetacean tissues, their potential relation to individual biological variables, or their trends over time. Here, the concentration of 10 BPs and 13 PAEs was assessed in the muscle of 30 striped dolphins (Stenella coeruleoalba) stranded along the Spanish Catalan coast (NW Mediterranean) between 1990 and 2018. Six BP and 6 PAE compounds were detected, of which only 4,4'-(cyclohexane-1,1-diyl)diphenol (BPZ) was detected in all the samples, at the highest concentration (mean 16.06 μg g-1 lipid weight). Sex or reproductive condition were largely uninfluential on concentrations: only dimethylphthalate (DMP) concentrations were significantly higher in immature individuals than in adults, and the overall PAE concentrations were significantly higher in males than in females. Temporal variations were only detected in bis(4-hydroxyphenyl)ethane (BPE), diethylphthalate (DEP) and dimethylphthalate (DMP), whose concentrations were lower, and 9,9-Bis(4-hydroxyphenyl)fluorene (BPFL), which were higher, respectively, in samples taken between 2014 and 2018, probably reflecting shifts in the production and use of these chemicals. These results provide the first assessment of concentrations of several BP and PAE compounds in the muscle of an odontocete cetacean.

Racial differences in the associations of urinary phthalate metabolites with depression risk

OBJECTIVE

This study aimed to investigate the composite effects of different kinds of phthalates on depression risk in the U.S population.

METHODS

11731 participants were included from the National Health and Nutrition Examination Survey (NHANES), a national cross-sectional survey. Twelve urinary phthalate metabolites were used to evaluate the level of phthalates exposure. Phthalates levels were devided into four quartiles. High phthalate was defined as having values in the highest quartile.

RESULTS

Urinary mono-isobutyl phthalate (MiBP) and mono-benzyl phthalate (MBzP) were estimated as the independent risk factors for depression by mutivariate logistic regression analyses. Compared with the lowest quartile group of MiBP or MBzP, an incrementally higher risk of depression and moderate/severe depression was observed in the highest quartile (all P_trend <0.05). It was observed that incrementally higher risk of depression and moderate/severe depression were associated with more numbers of high phthalates parameter (P_trend <0.001 and P_trend = 0.003, respectively). A significant interaction between race (Non-Hispanic Black vs. Mexican American) and 2 parameters (having value in the highest quartile of both MiBP and MBzP) was detected for depression (P_interaction = 0.023) and moderate/severe depression (P_interaction = 0.029).

CONCLUSION

Individuals with more numbers of high phthalates parameter were at higher risk of depression and moderate/severe depression. Non-Hispanic Black participants were more likely to be affected by high levels of MiBP and MBzP exposure than Mexican American participants.

Exposure to Phthalates in European Children, Adolescents and Adults since 2005: A Harmonized Approach Based on Existing HBM Data in the HBM4EU Initiative

Phthalates are mainly used as plasticizers and are associated inter alia with adverse effects on reproductive functions. While more and more national programs in Europe have started monitoring internal exposure to phthalates and its substitute 1,2-Cyclohexanedicarboxylic acid (DINCH), the comparability of results from such existing human biomonitoring (HBM) studies across Europe is challenging. They differ widely in time periods, study samples, degree of geographical coverage, design, analytical methodology, biomarker selection, and analytical quality assurance level. The HBM4EU initiative has gathered existing HBM data of 29 studies from participating countries, covering all European regions and Israel. The data were prepared and aggregated by a harmonized procedure with the aim to describe-as comparably as possible-the EU-wide general population's internal exposure to phthalates from the years 2005 to 2019. Most data were available from Northern (up to 6 studies and up to 13 time points), Western (11; 19), and Eastern Europe (9; 12), e.g., allowing for the investigation of time patterns. While the bandwidth of exposure was generally similar, we still observed regional differences for Butyl benzyl phthalate (BBzP), Di(2-ethylhexyl) phthalate (DEHP), Di-isononyl phthalate (DiNP), and Di-isobutyl phthalate (DiBP) with pronounced decreases over time in Northern and Western Europe, and to a lesser degree in Eastern Europe. Differences between age groups were visible for Di-n-butyl phthalate (DnBP), where children (3 to 5-year olds and 6 to 11-year olds) had lower urinary concentrations than adolescents (12 to 19-year-olds), who in turn had lower urinary concentrations than adults (20 to 39-year-olds). This study is a step towards making internal exposures to phthalates comparable across countries, although standardized data were not available, targeting European data sets harmonized with respect to data formatting and calculation of aggregated data (such as developed within HBM4EU), and highlights further suggestions for improved harmonization in future studies.

Screening for phthalates biomarkers and its potential role in infertility outcomes in Jordan

BACKGROUND

Phthalates are endocrine disrupting chemicals that are used in plastic and personal care products. Phthalate exposure has been linked to reproductive and fertility outcomes.

OBJECTIVES

This study aimed to assess the phthalate exposures using both urinary level of two DEHP metabolites in females and questionnaires. It also aimed to investigate the association between phthalate levels and reproductive and fertility outcomes.

METHODS

325 females with and without fertility problems at gynaecology clinics filled out a questionnaire and provided a urine sample. Urine samples were analyzed for two DEHP metabolites: MEHHP, mono (2-ethyl-5-hydroxyhexyl) phthalate; MEOHP, mono (2-ethyl-5-oxohexyl) phthalate, using an HPLC/MS/MS analytical method.

RESULTS

We observed a significant difference between cases and controls in terms of heating plastic in the microwave and use of skin and eye make-up, sunscreen, and nail polish. Our findings showed that MEOHP exposure is significantly associated with infertility among Jordanian women (Adjusted OR = 1.66, 95% CI: 1.14, 2.40, p-value = 0.002).

SIGNIFICANCE

To the best of our knowledge, our study is the first of its kind done in Jordan to screen for phthalate exposure and investigate its association with infertility. Our study demonstrated high exposure of the Jordanian population to DEHP. It confirms the association between DEHP exposure and infertility.

IMPACT STATEMENT

We measured phthalates in infertile and fertile women, in a community unaware of phthalate sources or its impacts, and with no regulation limits set. We aimed to increase awareness to environmental exposure to phthalates, emphasize the importance of implementation of public health interventions to control and minimize the effects of phthalate exposure and provide a base for further studies and future research to aid in the formation of policies and guidelines for the manufacturing and use of phthalates.

Trends in elemental Pb concentrations within atmospheric PM2.5 and associated risk to human health in major cities of China

High concentrations of elemental lead (Pb) in the atmosphere pose a serious threat to human health. This study presents and summarizes data obtained from relevant literature on Pb concentrations within fine particulate matter (PM_2.5) recorded in major cities in China from 2008 to 2019. An environmental health risk assessment model was then used to evaluate the health hazards of inhaling Pb among adults and children in China. Owing to the promulgation and implementation of a series of air pollution control measures, the Pb concentrations within PM_2.5 measured in major cities in China showed a downward trend after peaking in 2013. The concentrations were higher in winter than in summer, and higher in northern cities than in southern cities. Although the Pb concentrations in most cities did not exceed the limit (500 ng/m³) set by China, they remained much higher than concentrations recorded in developed countries. The results of the environmental health risk analysis showed that the non-carcinogenic risk from atmospheric Pb exposure was higher in children than in adults (adult females > adult males), while the carcinogenic risk was higher in adults than in children. This study shows that even if the health risk of Pb in PM_2.5 does not exceed the acceptable limit, stricter Pb pollution control measures are required to safeguard population health due to the dangers of Pb.

Dibutyl phthalate affects insulin synthesis and secretion by regulating the mitochondrial apoptotic pathway and oxidative stress in rat insulinoma cells

Dibutyl phthalate (DBP) is a typical phthalate (PAEs). The environmental health risks of DBP have gradually attracted attention due to the common use in the production of plastics, cosmetics and skin care products. DBP was associated with diabetes, but its mechanism is not clear. In this study, an in vitro culture system of rat insulinoma (INS-1) cells was established to explore the effect of DBP on insulin synthesis and secretion and the potential mechanisms. INS-1 cells were cultured in RPMI-1640 medium containing 10% fetal bovine serum and treated with 15, 30, 60 and 120 μmol/L of DBP and dimethyl sulfoxide (vehicle, < 0.1%) for 24 h. The contents of insulin in the intracellular fluid and the extracellular fluid of the cells were measured. The results showed that insulin synthesis and secretion in INS-1 cells were significantly decreased in 120 μmol/L DBP group. The apoptosis rate and mitochondrial membrane potential of INS-1 cells were measured by flow cytometry with annexin V-FITC conjugate and PI, and JC-1, respectively. The results showed that DBP caused an increase in the apoptosis rate and a significant decrease in the mitochondrial membrane potential in INS-1 cells in 60 μmol/L and 120 μmol/L DBP group. The results of western blot showed that the expression of Bax/Bcl-2, caspase-3, caspase-9 and Cyt-C were significantly increased. Meanwhile, the level of oxidative stress in INS-1 cells was detected by fluorescent probes DCFH-DA and western blot. With the increase of DBP exposure, the oxidative stress levels (MDA, GSH/GSSG) were increased; and the antioxidant index (SOD) levels were decreased. Our experimental results provide reliable evidence that DBP induced apoptosis and functional impairment in INS-1 cells through the mitochondrial apoptotic pathway and oxidative stress. Therefore, we hypothesized that interference with these two pathways could be considered in the development of preventive protection measures.

Techniques for remediation of pharmaceutical pollutants using metal organic framework - Review on toxicology, applications, and mechanism

Treatment of recalcitrant and xenobiotic pharmaceutical compounds in polluted waters have gained significant attention of the environmental scientists. Antibiotics are diffused into the environment widely owing to their high usages, very particularly in the last two years due to over consumption during covid 19 pandemic worldwide. Quinolones are very effective antibiotics, but do not get completely metabolized due to which they pose severe health hazards if discharged without proper treatment. The commonly reported treatment methods for quinolones are adsorption and advanced oxidation methods. In both the treatment methods, metal organic frameworks (MOF) have been proved to be promising materials used as stand-alone or combined technique. Many composite MOF materials synthesized from renewable, natural, and harmless materials by eco-friendly techniques have been reported to be effective in the treatment of quinolones. In the present article, special focus is given on the abatement of norfloxacin and ofloxacin contaminated wastewater using MOFs by adsorption, oxidation/ozonation, photocatalytic degradation, electro-fenton methods, etc. However, integration of adsorption with any advanced oxidation methods was found to be best remediation technique. Of various MOFs reported by several researchers, the MIL-101(Cr)-SO₃H composite was able to give 99% removal of norfloxacin by adsorption. The MIL - 88A(Fe) composite and Fe LDH carbon felt cathode were reported to yield 100% degradation of ofloxacin by photo-Fenton and electro-fenton methods respectively. The synthesis methods and mechanism of action of MOFs towards the treatment of norfloxacin and ofloxacin as reported by several investigation reports are also presented.

Urinary levels of parabens, phthalate metabolites, bisphenol A and plasticizer alternatives in a Belgian population: Time trend or impact of an awareness campaign?

A human biomonitoring study was carried out in 2015 within an adult population living in Liege (Belgium). Some phthalate metabolites and parabens were measured in the urine of 252 participants, and information were collected about their food habits, life styles and home environment to identify some predictors of exposure. Concomitantly, an awareness campaign was initiated by the Provincial Authorities of Liege and spread over 2 years. Three years later (2018), 92 of the initial participants provided again urine samples, and the levels of phthalate metabolites, phthalate substitute (DINCH), parabens, bisphenol-A and bisphenol alternatives (bisphenol-S, -F, -Z, -P) were determined and compared to those obtained in 2015 to assess time trends. In 2015, methyl- and ethylparaben were the most abundant parabens (P50 = 9.12 μg/L and 1.1 μg/L respectively), while propyl- and butylparaben were sparsely detected. Except for mono-2-ethylhexyl phthalate and 6-OH-mono-propyl-heptyl phthalate, all other targeted phthalate metabolites were positively quantified in most of the urine samples (between 89 and 98%) with median concentrations ranging between 2.7 μg/L and 21.3 μg/L depending on the metabolite. The multivariate regression models highlighted some significant associations between urinary phthalate metabolite or paraben levels and age, rural or urban character of the residence place, and the use of some personal care products. However, all determination coefficients were weak meaning that the usual covariates included in the models only explained a small part of the variance. Between 2015 and 2018, levels of parabens and phthalate metabolites significantly decreased (from 1.3 to 2.5 fold) except for monoethyl phthalate which seemed to remain quite constant. Contrariwise, all bisphenol alternatives and DINCH metabolites were measured in higher concentrations in 2018 vs 2015 while BPA levels did not differ significantly. However, it was not feasible to unequivocally highlight an impact of the awareness campaign on the exposure levels of the population.

Urinary metabolites and handwipe phthalate levels among adults and children in southern China: Implication for dermal exposure

Paired handwipe and urine samples were collected from adult (n = 130) and child (n = 82) residents of a typical urban community in southern China to examine relationships between external and internal exposure as well as the contribution of dermal absorption to the exposure of phthalates. The concentrations and composition profiles of phthalates were similar in handwipes from both adults and children, and contained mainly di-2-ethylhexyl phthalate (DEHP), di-n-butyl phthalate (DnBP) and di-iso-butyl phthalate (DiBP), consistent with profiles of phthalates in air and dust. The major metabolites of these phthalates, i.e., mono-n-butyl phthalate (mnBP) from DnBP, mono-iso-butyl phthalate (miBP) from DiBP and three metabolites of DEHP (namely mEHP, mEHHP and mEOHP) were widely detected in paired urine samples. Positive correlations were found between contamination levels of DiBP and DnBP in handwipes and their corresponding urinary metabolites, whereas no significant correlation was observed for DEHP. This suggests that dermal absorption might be an important exposure pathway particularly for low molecular weight phthalates. Our study shows that dermal absorption is a non-negligible exposure pathway for phthalates, to which children are particularly sensitive since the contribution of dermal uptake to the internal exposure of phthalates was higher in children than adults.

Concurrent Assessment of Phthalates/HEXAMOLL® DINCH Exposure and Wechsler Intelligence Scale for Children Performance in Three European Cohorts of the HBM4EU Aligned Studies

Information about the effects of phthalates and non-phthalate substitute cyclohexane-1,2-dicarboxylic acid diisononyl ester (HEXAMOLL^® DINCH) on children's neurodevelopment is limited. The aim of the present research is to evaluate the association between phthalate/HEXAMOLL^® DINCH exposure and child neurodevelopment in three European cohorts involved in HBM4EU Aligned Studies. Participating subjects were school-aged children belonging to the Northern Adriatic cohort II (NAC-II), Italy, Odense Child Cohort (OCC), Denmark, and PCB cohort, Slovakia. In each cohort, children's neurodevelopment was assessed through the Full-Scale Intelligence Quotient score (FSIQ) of the Wechsler Intelligence Scale of Children test using three different editions. The children's urine samples, collected for one point in time concurrently with the neurodevelopmental evaluation, were analyzed for several phthalates/HEXAMOLL^® DINCH biomarkers. The relation between phthalates/HEXAMOLL^® DINCH and FSIQ was explored by applying separate multiple linear regressions in each cohort. The means and standard deviations of FSIQ were 109 ± 11 (NAC-II), 98 ± 12 (OCC), and 81 ± 15 (PCB cohort). In NAC-II, direct associations between FSIQ and DEHP's biomarkers were found: 5OH-MEHP+5oxo-MEHP (β = 2.56; 95% CI 0.58-4.55; N = 270), 5OH-MEHP+5cx-MEPP (β = 2.48; 95% CI 0.47-4.49; N = 270) and 5OH-MEHP (β = 2.58; 95% CI 0.65-4.51; N = 270). On the contrary, in the OCC the relation between DEHP's biomarkers and FSIQ tended to be inverse but imprecise (p-value ≥ 0.10). No associations were found in the PCB cohort. FSIQ was not associated with HEXAMOLL^® DINCH in any cohort. In conclusion, these results do not provide evidence of an association between concurrent phthalate/DINCHHEXAMOLLR DINCH exposure and IQ in children.

Intrapopulation and temporal differences of phthalate concentrations in North Atlantic fin whales (Balaenoptera physalus)

The fin whale (Balaenoptera physalus) is a migratory filter-feeding species that is susceptible to ingest plastics while lunge feeding across the oceans. Plastic additives, such as phthalates, are compounds that are added to plastics to give them specific characteristics, such as flexibility. These so-called plasticizers are currently raising major concern because of their potential adverse effects on marine fauna. However, little is known about phthalate concentrations in tissues of baleen whales as well as their potential relation with biological variables (i.e., sex, body length and age) and their trends with time. In this study, we assessed the concentration of 13 phthalates in the muscle of 31 fin whales sampled in the feeding grounds off western Iceland between 1986 and 2015. We detected 5 of the 13 phthalates investigated, with di-n-butylphthalate (DBP), diethylphthalate (DEP) and bis(2-ethylhexyl) phthalate (DEHP) being the most abundant. None of the biological variables examined showed a statistically significant relationship with phthalate concentrations. Also, phthalate concentrations did not significantly vary over the 29-year period studied, a surprising result given the global scenario of increasing plastic pollution in the seas. The lack of time trends in phthalate concentration may be due in part to the fact that phthalates also originate from other sources. Although no adverse effects of phthalates on fin whales have been detected to date, further monitoring of these pollutants is required to identify potential toxic effects in the future.

Phthalate Esters in Tap Water, Southern Thailand: Daily Exposure and Cumulative Health Risk in Infants, Lactating Mothers, Pregnant and Nonpregnant Women

Human exposure to phthalate esters (PAEs) via drinking water has generated public health concerns due to their endocrine disruptive abilities. This study reports on the occurrence and fate of six PAEs in raw and tap water samples collected from provincial waterworks located in Songkhla Province, Southern Thailand. In addition, the daily exposure and cumulative health risk of susceptible populations due to drinking tap water were evaluated by using four different reference dose (RfDs) sources. The maximum concentrations of PAEs in raw water were between 1.68 and 4.84 and 0.52 and 1.24 µg/L in tap water. Moreover, the levels of PAEs in the tap water samples indicated the poor PAEs removal efficiency of the conventional treatment process (59.9-69.1%). The contribution of water to the daily intake of PAEs did not exceed 0.37% in all the groups. Furthermore, both the individual and cumulative risk assessment showed negligible noncarcinogenic and antiandrogenic risk for all the groups. Nevertheless, the cumulative risk showed an increasing trend in the order of infants > lactating mothers > pregnant women > nonpregnant women, suggesting that infants are more vulnerable. In additional, the newly proposed RfDAA yielded higher hazard quotient and hazard index estimates, which indicates it is a more sensitive tool than other RfDs for the assessment of the individual and mixture risk of pollutants. The carcinogenic risk of DEHP was acceptable in every group. However, we recommend a future cumulative risk assessment of vulnerable groups considering their simultaneous exposure to all chemicals that have antiandrogenic effects via tap water.

The relationship between urinary phthalate metabolites and polycystic ovary syndrome in women undergoing in vitro fertilization: Nested case-control study

Certain endocrine disruptor chemicals are involved in the pathogenesis of polycystic ovary syndrome (PCOS), a hormonal disease related to infertility in women. Phthalates are the most common plasticizers found in several consumer products. Experimental and epidemiologic evidence suggests that some phthalates disrupt endocrine functions in reproductive mechanisms and development. We previously measured the levels of eight phthalate metabolites in the urine of 599 Saudi women who underwent in vitro fertilization (IVF) treatment and were enrolled in a prospective study (2015-2017). The current nested case-control study aimed to determine the association between urinary levels of phthalate metabolites and PCOS. Overall, 441 women from the IVF study were identified as eligible for this study. Women in the case group included those diagnosed with PCOS (N = 82). The control group comprised those unable to conceive due to male azoospermia or who underwent preimplantation genetic diagnosis (N = 359). Most urinary phthalate metabolite levels were several-fold higher than those reported in national surveys from other countries. The ratio of luteinizing hormone to follicle-stimulating hormone, an index of PCOS, was significantly higher in the case than in the control group, with no indication of its association with phthalate metabolites. The logistic regression model was applied after adjusting for confounders to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each metabolite modeled as a natural logarithm (ln). For each ln-unit increase in the sum of the four di (2-ethylhexyl) phthalate (∑₄DEHP) metabolites as well as two individual metabolites, mono-(2-ethyl-5-oxohexyl) phthalate and mono-(2-ethyl-5-carboxypentyl) phthalate, the odds of PCOS increased by 40.5% [OR = 1.405 (95% CI: 1.025, 1.925)], 41.1% [OR = 1.055 (95% CI: 1.055, 1.885)], and 38.6% [OR = 1.386 (95% CI: 1.033, 1.86)], respectively. In contrast, the % odds of PCOS decreased marginally significantly by 44% [OR = 0.560 (95% CI: 0.313, 1.002)] with an ln-unit increase of %MEHP₄, the ratio of mono-(2-ethylhexyl) phthalate to ∑₄DEHP. These findings suggest that DEHP may contribute to PCOS, and further investigation is required to understand the underlying mechanisms.

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.

Review of the Existing Evidence for Sex-Specific Relationships between Prenatal Phthalate Exposure and Children's Neurodevelopment

Phthalates are well-known, ubiquitous environmental contaminants influencing children's health and their neurodevelopment. However, results of the previously conducted studies are not entirely conclusive. The aim of this review is to present the current state of knowledge with respect to the association between the prenatal phthalate exposure and sex-specific child neurodevelopmental outcomes. A systematic search of the literature was carried out to identify the studies that analyse the sex-specific association between prenatal exposure to phthalates and cognitive, psychomotor outcomes and behavioural and emotional problems. The search was conducted in May 2021, and it was limited to the papers published in English between January 2015 and April 2021. The following databases were used: PubMed, Scopus and Elsevier. The selection process was carried out by two independent authors according to the inclusion criteria. Of a total of 7542 records, 17 epidemiological studies met the inclusion criteria with regards to phthalate exposure and sex-specific differences in child neurobehavioural development. The review shows no clear pattern of association between maternal exposure to phthalates during pregnancy and offspring neurodevelopment. No clearly pronounced sex specific effects, except for BBzP exposure and decreased motor ablates among girls, have been indicated. Inconsistences in the results, as well as unsolved issues related to the interpretation of the results in the context of the exposure level, outcomes, confounders, and biological plausibility highlight the necessity for further research in the field.

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.

Levels and determinants of urinary phthalate metabolites in New Zealand children and adults

BACKGROUND

This first national biomonitoring survey of urinary phthalate metabolites in the New Zealand population aimed to provide baseline data, identify exposure determinants, and make comparisons with health-based exposure guidance values.

METHODS

The survey conducted in 2014-2016 involved the collection of morning-void urine from 298 children (5-18 years) and 302 adults (20-65 years), 33% of Māori ethnicity. A questionnaire collected information on demographic factors and diet. Urine was analysed for creatinine, specific gravity, and 10 phthalate metabolites through liquid chromatography tandem-mass spectrometry (MMP; MEP; MBP iso+n; MBzP; MCHP; MEHP; MEOHP; MEHHP; MCPP; and MiNP). Determinants of exposure were assessed using multivariable linear regression.

RESULTS

Detection frequencies exceeded 95% for metabolites of DEP, DEHP and DBP. The highest GM was observed for the DBP metabolite MBP iso+n (36.1 μg/L adults; 60.5 μg/L children), followed by the sum of three DEHP metabolites (MEHP+MEOHP+MEHHP: 19.0 μg/L adults; 37.0 μg/L children), and the DEP metabolite MEP (19.1 μg/L adults; 12.0 μg/L children). For most phthalate metabolites New Zealand levels were in the mid-range of internationally reported levels, while for DEP they were in the low range. Māori and non-Māori had similar levels. Children had higher GMs than adults for most metabolites, except for MEP. A proportion of children and adults exceeded the biomonitoring equivalents of health-based guidance values for DBP (0-16% and 0-3% respectively), and DEHP (0-0.7% and 0-0.3% respectively). Eating warm meals from plastic containers ≥2 times/week was associated with higher levels of DEHP metabolites, MBP iso+n, and MBzP.

CONCLUSION

Phthalate exposure is omnipresent in both children and adults in New Zealand. Exceedances of the biomonitoring equivalents for DBP and DEHP indicate that potential health effects from exposure to these phthalates cannot be excluded with sufficient certainty.

A critical review on human internal exposure of phthalate metabolites and the associated health risks

Phthalates (PAEs) are popular synthetic chemicals used as plasticizers and solvents for various products, such as polyvinyl chloride or personal care products. Human exposure to PAEs is associated with various diseases, resulting in PAE biomonitoring in humans. Inhalation, dietary ingestion, and dermal absorption are the major human exposure routes. However, estimating the actual exposure dose of PAEs via an external route is difficult. As a result, estimation by internal exposure has become the popular analytical methods to determine the concentrations of phthalate metabolites (mPAEs) in human matrices (such as urine, serum, breast milk, hair, and nails). The various exposure sources and patterns result in different composition profiles of PAEs in biomatrices, which vary from country to country. Nevertheless, the mPAEs of diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP), and di-(2-ethylhexyl) phthalate (DEHP) are predominant in the urine. These mPAEs have greater potential health risks for humans. Children have been observed to exhibit higher exposure risks to several mPAEs than adults. Besides age, other influencing factors for phthalate exposure are gender, jobs, and residential areas. Although many studies have reported biological monitoring of PAEs, only a few reviews that adequately summarized the reports are available. The current review appraised available studies on mPAE quantitation in human biomatrices and estimated the dose and health risks of phthalate exposure. While some countries lack biomonitoring data, some countries' data do not reflect the current PAE exposure. Thence, future studies should involve frequent PAE biomonitoring to accurately estimate human exposure to PAEs, which will contribute to health risk assessments of human exposure to PAEs. Such would aid the formulation of corresponding regulations and restrictions by the government.

Phthalates and Their Impacts on Human Health

Phthalates are a series of widely used chemicals that demonstrate to be endocrine disruptors and are detrimental to human health. Phthalates can be found in most products that have contact with plastics during producing, packaging, or delivering. Despite the short half-lives in tissues, chronic exposure to phthalates will adversely influence the endocrine system and functioning of multiple organs, which has negative long-term impacts on the success of pregnancy, child growth and development, and reproductive systems in both young children and adolescents. Several countries have established restrictions and regulations on some types of phthalates; however, we think that more countries should establish constraints or substitute measures for phthalates to reduce health risks. This article aims to summarize the adverse impacts of phthalates on human health, analyze the toxicity mechanism, assess the risks, and finally provide feasible strategies to reduce exposure of the public to phthalates.

Demographic Assessment of Mono(2-ethylhexyl) Phthalate (MEHP) and Monoethyl Phthalate (MEP) Concentrations in Common Bottlenose Dolphins (Tursiops truncatus) From Sarasota Bay, FL, USA

Common bottlenose dolphins (Tursiops truncatus) have previously demonstrated exposure to phthalate esters. Phthalates and phthalate esters are commonly added to consumer goods to enhance desirable properties. As the amount of plastic marine debris increases, these chemicals can easily leach from these products into the surrounding environment. To evaluate demographic variability in exposure, eight phthalate metabolites were quantified in urine samples collected from free-ranging bottlenose dolphins sampled in Sarasota Bay, FL, USA (2010-2019; n = 51). Approximately 75% of individual dolphins had detectable concentrations of at least one phthalate metabolite. The most frequently detected metabolites were mono(2-ethylhexyl) phthalate (MEHP; n = 28; GM = 4.57 ng/mL; 95% CI = 2.37-8.80; KM mean = 7.95; s.d. = 15.88) and monoethyl phthalate (MEP; GM = 4.51 ng/mL; 95% CI = 2.77-7.34; ROS mean = 2.24; s.d. = 5.58). Urinary concentrations of MEHP and MEP were not significantly different between sex (MEHP p = 0.09; MEP p = 0.22) or age class (i.e., calf/juvenile vs. adult; MEHP p = 0.67; MEP p = 0.13). Additionally, there were no significant group differences in the likelihood of MEHP or MEP detection for any demographic as determined by a Peto-Peto test. Frequency of detection was similar for both metabolites between males and females (MEHP p = 0.10; MEP p = 0.40) as well as between juveniles and adults (MEHP p = 0.50; MEP: p = 0.60). These findings suggest ubiquitous exposure risk for both sexes and age classes, warranting further investigation into potential sources and health implications.

Levels and determinants of urinary phthalate metabolites in Chinese community-dwelling older adults

BACKGROUND

Biomonitoring studies have demonstrated extensive exposure of infants, children, and pregnant women to phthalates, but data on phthalate exposure and their determinants in Chinese older adults remain insufficient. This study aims to assess urinary phthalate metabolite levels, individual and cumulative exposure risk, and their determinants in Chinese community-dwelling older adults.

METHODS

A total of 987 individuals aged 60 years or over were included in this study. The urinary levels of seven phthalate metabolites were measured using high-performance liquid chromatography-tandem mass spectrometry. The estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) of phthalates were calculated based on urinary metabolite levels. The associations between phthalate metabolite levels and potential determinants were examined using multiple linear regressions.

RESULTS

Detection rates of seven phthalate metabolites from the study population ranged from 63.83% to 99.39%. The highest median concentration was 43.64 μg/L (42.59 μg/g creatinine) for mono-butyl phthalate (MBP). The highest median EDI was 1.55 μg/kg-bw/day for diethyl phthalate (DBP). Nearly 5% of participants had high HI values exceeding 1, mainly attributed to DBP and di-2-ethylhexyl phthalate (DEHP). Furthermore, we found that females, higher body mass index (BMI), smoking, having two or more chronic diseases, and vegetable-based diets were significantly associated with higher levels of parts of phthalate metabolites. More interestingly, higher urine levels of high-molecular-weight (HMW) phthalate metabolites and lower urine levels of low-molecular-weight (LMW) phthalate metabolites were found in rural older adults than in urban older adults.

CONCLUSIONS

Chinese community-dwelling older adults are extensively exposed to phthalates, especially to DBP and DEHP. More attention should be paid to urban-rural differences in exposure to HMW and LMW phthalates and to phthalate exposure among older adults with overweight/obesity, females, and individuals who are current heavy smokers, have two or more chronic diseases, and consume vegetable-based diets.

Secular trends of urinary phthalate metabolites in 7-year old children and association with building characteristics: Hokkaido study on environment and children's health

The widespread commercial production and use of phthalates as plasticizers in consumer products have led to significant human exposure. Some phthalates are known to disrupt the endocrine system and result in adverse health outcomes. As such, they have been regulated in materials used for children's items and food packages. In this study, we examined the secular trend of urinary phthalate metabolites in children and the association between metabolites and building characteristics. In total, 400 first-morning spot urine samples of 7 years old children collected from 2012 to 2017 from an ongoing birth cohort study were examined. Parents provided information on demographics and building questionnaires. We analyzed 10 urinary phthalate metabolites from five phthalate diesters using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS): MiBP, MnBP, MBzP, MEHP, MEOHP, MEHHP, MECPP, MiNP, OH-MiNP, and cx-MiNP. A multivariable regression model with creatinine-corrected metabolite levels was applied to assess secular trends during 2012-2017. The association between metabolite levels and building characteristics was investigated using a mutual-adjusted linear regression. The metabolites MnBP, MEHP, MEOHP, MEHHP, MECPP, and OH-MiNP were detected in all samples. The highest median concentration was for MECPP 37.4 ng/mL, followed by MnBP and MEHHP at concentrations of 36.8 and 25.8 ng/mL, respectively. Overall, DBP, BBzP, and DINP metabolite concentrations in this study were comparable to or lower than those in previous studies from Japan and other countries in a similar study period. Higher concentrations of DEHP metabolites were observed in this study than in children from the USA and Germany, as per previous reports. Despite updated phthalate regulations and reports of production volume change in Japan, all the measured metabolites showed a stable trend between 2012 and 2017. Higher phthalate metabolite levels were observed among children from households with low annual income, those who lived in old buildings, and those with window opening habits of ≥1 h than ≤1 h. In contrast, children in houses that vacuumed 4 or more days/week showed a lower level of MnBP than those in houses that vacuumed ≤3 days/week. This study demonstrates that the internal exposure level of phthalates in Japanese children was stable from 2012 to 2017. Our findings suggest that phthalate exposure in children is consistent. Thus, improvements in the indoor environment, such as frequent vacuuming, may reduce exposure. Biomonitoring of phthalates is critical for elucidating their possible health effects and developing mitigation strategies.

The European Human Biomonitoring Initiative (HBM4EU): Human biomonitoring guidance values for selected phthalates and a substitute plasticizer

Ubiquitous use of plasticizers has led to a widespread internal exposure of the European population. Until today, metabolites are detected in almost every urine sample analysed. This raised the urgent need for a toxicological interpretation of the internal exposure levels. The European Human Biomonitoring Initiative (HBM4EU) contributes substantially to the knowledge on the actual exposure of European citizens to chemicals prioritised within HBM4EU, on their potential impact on health and on the interpretation of these data to improve policy making. On that account, human biomonitoring guidance values (HBM-GVs) are derived for the general population and the occupationally exposed population agreed at HBM4EU consortium level. These values can be used to assess phthalate exposure levels measured in HBM studies in a health risk assessment context. HBM-GVs were derived for five phthalates (DEHP, DnBP, DiBP, BBzP and DPHP) and for the non-phthalate substitute Hexamoll® DINCH. For the adult general population, the HBM-GVs for the specific metabolite(s) of the respective parent compounds in urine are the following: 0.5 mg/L for the sum of 5-oxo-MEHP and 5-OH-MEHP; 0.19 mg/L for MnBP, 0.23 mg/L for MiBP; 3 mg/L for MBzP; 0.5 mg/L for the sum of oxo-MPHP and OH-MPHP and 4.5 mg/L for the sum of OH-MINCH and cx-MINCH. The present paper further specifies HBM-GVs for children and for workers.

Parabens in urine of children and adolescents in Germany - human biomonitoring results of the german environmental survey 2014-2017 (GerES V)

Parabens are antimicrobial preservatives used in a wide range of consumer products such as personal care products, cosmetics, pharmaceuticals, and food. Consequently, the general population is ubiquitously exposed to these substances via dermal absorption, ingestion, and inhalation. Parabens promote estrogenic activity and are hence under assessment as endocrine disrupting substances. Urine samples from 3- to 17-year-old children and adolescents (N = 516) living in Germany were analysed for concentrations of nine parabens in the population representative German Environmental Survey for Children and Adolescents 2014-2017 (GerES V). Detection rates and urinary concentrations of the parabens decreased with increasing length of the alkyl chain. Methyl paraben was quantified in 97% of the samples with a geometric mean (GM) concentration of 7.724 μg/L (6.714 μg/g_creatinine), ethyl paraben was quantified in 69% (GM: 0.943 μg/L and 0.825 μg/g_crea), and n-propyl paraben in 31% (GM: 0.563 μg/L and 0.493 μg/g_crea). Concentrations of iso-propyl paraben, butyl paraben, iso-butyl paraben, and benzyl paraben were below the limit of quantification in most samples. Pentyl paraben and heptyl paraben were not detected in any of the samples. Paraben concentrations in urine were found to be associated with frequent usage of leave-on personal care products and cosmetics. Cumulative exposure to parabens (back-calculated daily intakes, expressed as hazard index) was found to be on a level raising concern in up to 14% of the population, mainly driven by n-propyl paraben, and depending on the level of conservativeness and point-of departures used for calculation.

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).

Genotoxic risk assessment and mechanism of DNA damage induced by phthalates and their metabolites in human peripheral blood mononuclear cells

The human genome is persistently exposed to damage caused by xenobiotics, therefore the assessment of genotoxicity of substances having a direct contact with humans is of importance. Phthalates are commonly used in industrial applications. Widespread exposure to phthalates has been evidenced by their presence in human body fluids. We have assessed the genotoxic potential of selected phthalates and mechanism of their action in human peripheral blood mononuclear cells (PBMCs). Studied cells were incubated with di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP) and their metabolites: mono-n-butylphthalate (MBP), mono-benzylphthalate (MBzP) in the concentrations range of 0.1-10 µg/mL for 24 h. Analyzed compounds induced DNA single and double strand-breaks (DBP and BBP ≥ 0.5 µg/mL, MBP and MBzP ≥ 1 µg/mL) and more strongly oxidized purines than pyrimidines. None of the compounds examined was capable of creating adducts with DNA. All studied phthalates caused an increase of total ROS level, while hydroxyl radical was generated mostly by DBP and BBP. PBMCs exposed to DBP and BBP could not completely repair DNA strand-breaks during 120 min of postincubation, in opposite to damage caused by their metabolites, MBP and MBzP. We have concluded that parent phthalates: DBP and BBP caused more pronounced DNA damage compared to their metabolites.

Co-exposure to polycyclic aromatic hydrocarbons and phthalates and their associations with oxidative stress damage in school children from South China

Monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), phthalate metabolites (mPAEs), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the urine of school children aged 8-11 years from Shenzhen, China were measured in order to investigate oxidative stress damage from co-exposure to PAHs and PAEs. The concentrations of OH-PAHs and mPAEs in urine were 0.36-36.5 (median: 3.86) and 9.48-1609 (median: 240) ng/mL respectively. Gender and age did not influence urinary concentrations of ΣOH-PAHs and ΣmPAEs, but geographical variations (i.e., urban versus suburban) were observed. Levels of 8-OHdG were positively correlated with urinary OH-PAHs and mPAEs, with correlation coefficients (r) varying between 0.160 and 0.365 (p < 0.05). OH-PAHs made a greater contribution to oxidative DNA damage than mPAEs when these two types of pollutants were present at the same concentrations. Human health risks were assessed using the hazard quotient and the hazard index for the cumulative risk of a complex of chemicals. The results demonstrated that risks from PAHs could be neglected, but that 29.5 % of school children may be subject to obvious health risks from PAEs, especially diethylhexyl phthalate.

Prenatal and childhood exposure to phthalic acid esters and vaccination antibodies in children: A 15-year follow-up birth cohort study

Phthalic acid esters (PAE) are widely used during chemical synthesis and do not form covalent linkages with products. It has been reported that exposure to PAE affects the immune response. However, their effect on antibody concentrations in children is still under investigation. We aimed to examine the association between early-life phthalate exposure and antibody concentrations in children in a longitudinal birth cohort established in 2000-2001. We recruited 398 neonates in central Taiwan and followed them up every 2-3 years, with various antibody-related studies at 11- and 14-year follow-ups. Seven urinary phthalate metabolites were quantified in mothers during pregnancy and children aged 11 years. Four antibody concentrations were analyzed in children aged 11 and 14 years. The percent change in antibody concentrations from ages 11 to 14 years was calculated and its association with phthalate exposure was evaluated via multivariate regression analysis. Eighty-one followed-up children were with sufficient data. After adjusting for prenatal exposure and other confounders, double concentrations of the urinary sum of di-2-ethylhexyl phthalate (ΣDEHPm) and mono-n-butyl phthalate (MnBP) were associated with a 18.06% (95% CI = 3.34%, 32.78%) and 22.53% decrease (95% CI = 3.39%, 41.66%) in antibody concentration against hepatitis B, respectively. Phthalate exposure was found to be related to decreased antibody concentrations against hepatitis B (DEHP, DBnP) in the early teens. This exposure is suggested to be considered for clinical re-booster vaccines among junior high school students. Further verification with additional cohorts and studies on the underlying mechanisms of phthalate exposure are warranted.

Phthalate exposure linked to high blood pressure in Chinese children

BACKGROUND

Exposure to phthalate esters may be linked to the risk of high blood pressure (HBP), but limited evidence is available in Chinese children.

OBJECTIVE

To investigate the associations between nine phthalate metabolites (mPAEs) and systolic/diastolic BP, pulse pressure (PP), mean arterial pressure (MAP), and the risk of HBP.

METHODS

In this cross-sectional study, a total of 1044 primary school children (6-8 years old) were enrolled from Shenzhen, China, between 2016 and 2017. Nine mPAEs were analyzed from urine using ultra-performance liquid chromatography and tandem mass spectrometry. A multivariable linear regression model was used to explore the associations between phthalate exposure and systolic/diastolic BP, PP, and MAP. A binary logistic regression model was used to examine the associations between phthalate exposure and the risk of HBP.

RESULTS

Monomethyl phthalate (MMP) concentrations were significantly higher in HBP children than normal BP children. MMP, monoisobutyl phthalate (MiBP), monobutyl phthalate (MnBP), mono(5-carboxy-2-ethylpentyl) phthalate, mono-[(2-carboxy methyl)hexyl] phthalate (MCMHP), the sum of four short-chain mPAEs (∑LMW), and the sum of all nine mPAEs (∑₉mPAEs) were significantly positively associated with increases in systolic BP z-score, while only MMP was significantly positively associated with diastolic BP z-score. MMP, MiBP, MnBP, MCMHP, ∑LMW, and ∑₉mPAEs were significantly associated with increases in PP, while MMP and MnBP were significantly associated with increases in MAP. MMP was significantly associated with the risk of HBP, with an odds ratio of 1.87 (95% CI: 1.23, 2.85).

CONCLUSIONS

The present study suggests that dimethyl phthalate exposure increases the risk of HBP. And some types of phthalates are associated with elevations in systolic/diastolic BP z scores, PP, and MAP in Chinese children.

Association of urinary phthalates metabolites concentration with emotional symptoms in Chinese university students

Previous studies have shown the associations between phthalates exposure and psychological behavior problems in children and adolescents, but such associations have not been fully elucidated in university students, especially among Chinese university students. This study aims to examine the association between urinary phthalates metabolites concentration and emotional symptoms in Chinese university students. A school-based cross-sectional survey was carried out among 990 university students aged 17-24 years from two universities in Anhui and Jiangxi provinces of China. Concentration of six phthalate metabolites in urine was determined by high-performance liquid chromatography-tandem mass spectrometry and the emotional symptoms were assessed by the 21-item Depression, Anxiety, and Stress Scale. The detection rate of six phthalate metabolites in urine ranged from 79.6% to 99.7%. The median concentration of six phthalate metabolites ranged from 2.90 to 119.64 ng/mL. The positive rates of depressive symptoms, anxiety symptoms, and stress were 17.4%, 24.8%, and 9.5%, respectively. After adjusting for the confounding variables, mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) was found to be associated with depressive symptoms (β = 8.84, P = 0.017), anxiety symptoms (β = 8.46, P = 0.015), and stress symptoms (β = 9.95, P = 0.012) in males; whereas, monobutyl phthalate (MBP) was found to be associated with depressive symptoms (β = 1.86, P = 0.002), anxiety symptoms (β = 1.81, P = 0.005), and stress symptoms (β = 1.48, P = 0.047) in females. Our study demonstrates that Chinese university students are widely exposed to phthalates; and high- and low-molecular weight phthalates are associated with emotional symptoms in males and females, respectively.

Human Erythrocytes Exposed to Phthalates and Their Metabolites Alter Antioxidant Enzyme Activity and Hemoglobin Oxidation

Phthalates used as plasticizers have become a part of human life because of their important role in various industries. Human exposure to these compounds is unavoidable, and therefore their mechanisms of toxicity should be investigated. Due to their structure and function, human erythrocytes are increasingly used as a cell model for testing the in vitro toxicity of various xenobiotics. Therefore, the purpose of our study was to assess the effect of selected phthalates on methemoglobin (metHb), reactive oxygen species (ROS) including hydroxyl radical levels, as well as the activity of antioxidative enzymes, such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), in human erythrocytes. Erythrocytes were incubated with di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), and their metabolites, i.e., mono-n-butyl phthalate (MBP) and monobenzyl phthalate (MBzP), at concentrations ranging from 0.5 to 100 µg/mL for 6 or 24 h. This study shows that the analyzed phthalates disturbed the redox balance in human erythrocytes. DBP and BBP, at much lower concentrations than their metabolites, caused a statistically significant increase of metHb and ROS, including hydroxyl radical levels, and changed the activity of antioxidant enzymes. The studied phthalates disturbed the redox balance in human erythrocytes, which may contribute to the accelerated removal of these cells from the circulation.

Intakes of phthalates by Japanese children and the contribution of indoor air quality in their residences

Some phthalates, which are used mainly as plasticizers, are suspected to be endocrine disruptors. In the present study, daily intakes of phthalates by Japanese children through all exposure pathways and the contribution of indoor air quality to the intakes were examined by measuring urinary phthalate metabolites in the children and the airborne phthalates in their residences. Spot urine samples excreted first after waking up in the morning were collected from the subjects aged 6 to 15 years (n = 132), and airborne phthalates were sampled in the subjects' bedrooms for 24 h. Eight airborne phthalates and their urinary metabolites were determined by gas chromatography/mass spectrometry. The daily intakes of the phthalates estimated were as follows (median, μg/kg b.w./day): dimethyl phthalate (DMP), 0.15; diethyl phthalate (DEP), 0.42; diisobutyl phthalate (DiBP), 1.1; di-n-butyl phthalate (DnBP), 2.2; dicyclohexyl phthalate (DcHP), 0.026; benzylbutyl phthalate (BBzP), 0.032; di(2-ethylhexyl) phthalate (DEHP), 6.3. The 95th percentile (21 μg/kg b.w./day) of the DEHP intakes exceeded the reference doses (RfD, 20 μg/kg b.w./day) of the US Environmental Protection Agency (EPA). DEHP was suggested to be the most notable phthalate from the perspective of adverse effects on the health of Japanese children. On the other hand, DcHP and di-n-hexyl phthalate were not considered to be very important as indoor air pollutants and as internal contaminants for the children. The contribution rates of the amounts absorbed by inhalation to the amounts absorbed via all of the exposure pathways were only 7.9, 4.4, 6.6, 3.2, 0.22, and 1.0% as the median for DMP, DEP, DiBP, DnBP, BBzP, and DEHP, respectively. Therefore, inhalation did not seem to contribute very much as an absorption pathway of the phthalates for Japanese children while at home.

Investigation of phthalate metabolites in urine and daily phthalate intakes among three age groups in Beijing, China

Phthalates are widely used as binders and plasticizers in industrial and consumer products but show diverse toxicity. We investigated the level of human exposure to phthalates in Beijing, one of the most densely populated cities in the world. In this study, 12 metabolites of phthalates were measured in 70 spot urine samples collected from Beijing residents from August 2017 to April 2018 using ultra high-performance liquid chromatography tandem mass spectrometry. We found that metabolites of phthalates were ubiquitous in all urine samples. Total concentrations of phthalate metabolites ranged from 39.6 to 1931 ng mL^-1, with median concentrations were in decreasing order of children (371 ng mL^-1)> younger adults (332 ng mL^-1)> older adults (276 ng mL^-1). Mono-n-butyl phthalate (MnBP) was the predominant compound, and occurred at concentrations greater than those reported for people in other countries. The mean values of estimated daily intakes (EDIs) of ∑phthalate were 35.2, 10.3 and 10.9 ng (kg-bm)^-1 d^-1 for children, younger adults and older adults, respectively. EDIs of di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP) and di-(2-ethylhexyl) phthalate (DEHP) exceeded reference values suggested by the US Environmental Protection Agency and the European Food Safety Authority. When concentrations were normalized to volume or creatinine-adjusted, hazard quotients (HQs) for 40 of 70 participants exhibited larger HQs >1 for individual phthalates, which was indicative of potential for adverse effects. Thus, exposure to phthalates might be a critical factor contributing to adverse health effects in Beijing residents. To the best of our knowledge, this is the first study to establish a pre-baseline level of urinary phthalate metabolites among residents in Beijing.

Risk assessment for humans using physiologically based pharmacokinetic model of diethyl phthalate and its major metabolite, monoethyl phthalate

Diethyl phthalate (DEP) belongs to phthalates with short alkyl chains. It is a substance frequently used to make various products. Thus, humans are widely exposed to DEP from the surrounding environment such as food, soil, air, and water. As previously reported in many studies, DEP is an endocrine disruptor with reproductive toxicity. Monoethyl phthalate (MEP), a major metabolite of DEP in vivo, is a biomarker for DEP exposure assessment. It is also an endocrine disruptor with reproductive toxicity, similar to DEP. However, toxicokinetic studies on both MEP and DEP have not been reported in detail yet. Therefore, the objective of this study was to evaluate and develop physiologically based pharmacokinetic (PBPK) model for both DEP and MEP in rats and extend this to human risk assessment based on human exposure. This study was conducted in vivo after intravenous or oral administration of DEP into female (2 mg/kg dose) and male (0.1-10 mg/kg dose) rats. Biological samples consisted of urine, plasma, and 11 different tissues. These samples were analyzed using UPLC-ESI-MS/MS method. For DEP, the tissue to plasma partition coefficient was the highest in the kidney, followed by that in the liver. For MEP, the tissue to plasma partition coefficient was the highest in the liver. It was less than unity in all other tissues. Plasma, urine, and fecal samples were also obtained after IV administration of MEP (10 mg/kg dose) to male rats. All results were reflected in a model developed in this study, including in vivo conversion from DEP to MEP. Predicted concentrations of DEP and MEP in rat urine, plasma, and tissue samples using the developed PBPK model fitted well with observed values. We then extrapolated the PBPK model in rats to a human PBPK model of DEP and MEP based on human physiological parameters. Reference dose of 0.63 mg/kg/day (or 0.18 mg/kg/day) for DEP and external doses of 0.246 μg/kg/day (pregnant), 0.193 μg/kg/day (fetus), 1.005-1.253 μg/kg/day (adults), 0.356-0.376 μg/kg/day (adolescents), and 0.595-0.603 μg/kg/day (children) for DEP for human risk assessment were estimated using Korean biomonitoring values. Our study provides valuable insight into human health risk assessment regarding DEP exposure.

Urinary monohydroxylated polycyclic aromatic hydrocarbons in primiparas from Shenzhen, South China: Levels, risk factors, and oxidative stress

The main objectives of the present study were to investigate urinary monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) in 77 primiparas who live in Shenzhen, Guangdong Province, China, and their association with 8-hydroxy-2'-deoxyguanosine (8-OHdG) and human health risks. High detection frequencies of OH-PAHs demonstrated the wide occurrence of chemicals in the human exposure to PAHs. The urinary concentrations of Σ₇OH-PAHs ranged from 1.37 to 45.5 ng/mL, and the median concentrations of 1-hydroxynaphthalene (1-OHN), 2-hydroxynaphthalene (2-OHN), 2-hydoxyfluorene (2-OHF), ΣOHPhe (the sum of 1-, 2+ 3-hydroxyphenanthrene), and 1-hydroxypyrene (1-OHP) were 3.00, 2.58, 0.31, 0.44, and 0.51 ng/mL, respectively. In the sum concentration of seven OH-PAHs, 1-OHN accounted for the largest proportion (43.7% of Σ₇OH-PAHs), followed by 2-OHN (37.1%), 2-OHF (4.94%), 1-OHP (8.01%), 1-OHPhe (4.79%), and 2+3-OHPhe (1.46%). The present results showed that vehicle exhaust and petrochemical emission are the main sources of PAHs in primiparas in Shenzhen, and inhalation is the most important exposure route. The living conditions have a significant influence on human exposure to PAHs. The concentrations of 8-OHdG were positively correlated with OH-PAH concentrations in urine because evidence suggested that urinary 8-OHdG levels can be considered as a biomarker of oxidative DNA damage. Hazard quotient was used to assess the human health risks from exposure to single compound, and hazard index was used to assess the cumulative risks of the compounds, which demonstrated that the exposure risks from PAHs in primiparas were relatively low.

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.

Longitudinal effect of phthalates exposure on allergic diseases in children

BACKGROUND

Environmental chemicals, such as phthalates, phenols, and parabens, may affect children's immune development and contribute to the risk of atopic diseases and asthma.

OBJECTIVE

To evaluate the associations between prenatal and childhood phthalate exposure and atopic diseases in children at the age of 9 years.

METHODS

This analysis is restricted to 145 mother-child pairs from the prospective Polish Mother and Child Cohort Study. Phthalate metabolite levels were assessed in the urine samples collected from mothers during the third trimester of pregnancy and from children at age of 2 and 9 years. For the appropriate recognition of children's health status, a questionnaire was administered to the mothers and completed with information from the medical record of each child. The clinical examination was performed by a pediatrician/allergist in the presence of the mother or a relative.

RESULTS

A higher urine concentration of mono-2-ethyl-5-oxohexyl phthalate increased the risk of food allergy in children at the age of 9 years (odds ratio [OR], 1.75; 95% CI, 1.19-2.57; P = .004) and decreased the risk of atopic dermatitis (OR, 0.49; 95% CI, 0.27-0.87; P = .02). For mono-2-ethyl-5-hydroxyhexyl phthalate, an increased risk of atopic dermatitis was observed (OR, 1.90; 95% CI, 1.18-3.05; P = .008). A higher urine concentration of mono-benzyl phthalate increased the risk of asthma in children (OR, 1.67; 95% CI, 1.08-2.58; P = .02), but the risk of asthma decreased when the concentration of mono-2-ethylhexyl phthalate was higher (OR, 0.64; 95% CI, 10.43-0.97; P = .04).

CONCLUSION

Our study has not provided clear evidence of the negative effect of phthalate exposure during pregnancy and within the 9 years after birth on allergic diseases in children.

Antibiotic exposure across three generations from Chinese families and cumulative health risk

Extensive antibiotic exposure in the general population has been documented by bio-monitoring, but data regarding antibiotic burden across three generations in families living in the same household are lacking. We investigated the distribution of antibiotics and the potential health risk among the three generations by selecting 691 participants from 256 households in Fuyang city, China. A total of 45 antibiotics and two metabolites were screened in urine samples through liquid chromatography electrospray tandem mass spectrometry. In total, 34 antibiotics were found in the samples with an overall detection frequency of 92.0%, and the detection frequencies of individual antibiotic ranged from 0.3% to 28.7%. Specifically, the concentrations of seven antibiotics (azithromycin, amoxicillin, oxytetracycline, levofloxacin, norfloxacin, trimethoprim and sulfamethoxazole) were extremely high (i.e., above 10, 000 ng/mL). The detection rates of tetracyclines were significantly different among the three generations, with parents having the highest detection rate. Penicillin V, chlortetracycline, doxycycline, enrofloxacin, and ciprofloxacin showed a higher detection frequency in parents, whereas tetracycline, danofloxacin, and ofloxacin were more likely to be found in grandparents. The proportions of the sum of the daily exposure dose of VAs and PVAs more than 1 μg/kg/d in children, parents, and grandparents were 31.6%, 39.5%, and 26.5%, respectively. A hazard index (HI) greater than 1 was observed in 14.7% children, which was less than the 23.6% in parents and slightly higher than the 11.8% in grandparents. Ciprofloxacin was the biggest contributor to HI among the three generations. Collectively, these findings indicate that households are widely exposed to various antibiotics in Fuyang city, where parents had the highest health risk associated with the disturbance of gut microbiota.

SREBP2-STARD4 is involved in synthesis of cholesteryl ester stimulated by mono-butyl phthalate in MLTC-1 cells

Sterol is synthesized from cholesterol which is from the hydrolysis of stored cholesteryl esters. The process of maintaining cholesterol homeostasis is regulated by SREBP2-STARD4. Lots of researches demonstrated that male steroidogenesis could be interfered by di-n-butyl phthalate (DBP) or monobutyl phthalate (MBP). However, mechanisms of MBP exposure in this process have not been uncovered clearly. The objectiveof this study was to explore roles of SREBP2 and STARD4 in cholesteryl estersynthesis stimulated by MBP in mouse Leydig tumor cells (MLTC-1). MLTC-1 exposedto 10-8, 10-7, 10-6, 10-5 M MBP showed that levels of cholestery ester were increased significantly at 10-7 M MBP. Besides, cholesteryl ester synthesis stimulated by MBP was down-regulate when STARD4 or SREBP2 were inhibited. Activity of SREBP2 binding to the promoter of STARD4 was increased after MBP exposure. This study suggests that MBP can increase cholesteryl ester synthesis through SREBP2-STARD4 signal pathway in MLTC-1 cells.

Cumulative risk assessment of phthalates in edible vegetable oil consumed by Chinese residents

BACKGROUND

Phthalates have been widely used as plasticizers in various industries and are widely focused on in the international community as a result of their reproductive toxicity. Exposure of Chinese residents to phthalates via edible vegetable oil occurs often. In the present study, gas chromatography-mass spectrometry was used to detect the two main phthalates bis(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) in four major edible vegetable oil sources: an edible oil blend, soybean oil, peanut oil and rapeseed oil (a total of 1016 samples), as collected throughout China. Furthermore, cumulative risk assessment was used to estimate the reproductive health risk to Chinese residents caused by the phthalates that come from edible vegetable oils.

RESULTS

Both phthalates were detected in four major edible vegetable oil sources. The phthalate with the highest detection rate was DBP (13.48%), followed by DEHP (7.78%). The results of the cumulative risk assessment showed that the hazard indices of these two phthalates in edible vegetable oils were less than 1, except in soybean oil. Nevertheless, the two phthalates had the lowest detection rates in soybean oil, which were 1.94% (DEHP) and 5.16% (DBP). In China, contamination levels of phthalates in the soils where oil crops are cultivated have a great influence on the phthalate concentrations in edible vegetable oils.

CONCLUSION

It is recommended that Chinese residents who are consuming soybean oil choose well-known brands and regularly change their brand of consumption. The phthalates in edible vegetable oils pose a relatively small reproductive health risk to Chinese residents. © 2019 Society of Chemical Industry.

Harmonizing analytical chemistry and clinical epidemiology for human biomonitoring studies. A case-study of plastic product chemicals in urine

There is an interdisciplinary interface between analytical chemistry and epidemiology studies with respect to the design, execution, and analysis of environmental epidemiology cohorts and studies. Extracting meaningful results linking chemical exposure to human health outcomes begins at study design and spans the entire workflow. Here we discuss analytical experimental design from an exposure science perspective, and propose a reporting checklist for the design of human biomonitoring studies. We explain key analytical chemistry concepts of blanks and limits of reporting and present a case series of plastic product chemical exposure in prenatal urine specimens from the Barwon Infant Study.

Which chemicals should be grouped together for mixture risk assessments of male reproductive disorders?

There is concern about cumulative exposures to compounds that disrupt male sexual differentiation in foetal life, leading to irreversible effects in adulthood, including declines in semen quality, testes non-descent, malformations of the penis and testis cancer. Traditional chemical-by-chemical risk assessment approaches cannot capture the likely cumulative health risks. Past efforts of focusing on combinations of phthalates, a subgroup of chemicals suspected of contributing to these risks, do not go far enough, as they ignore the contribution of other types of chemicals. With the aim of providing criteria for the inclusion of additional chemicals in mixture risks assessments for male reproductive health, this paper examines the mechanisms of action of various chemicals capable of disrupting male sexual differentiation. An Adverse Outcome Pathway (AOP) network for malformations of the male reproductive system is constructed that includes new findings about the role of disruptions of prostaglandin signalling. This network is used to identify pathways that converge at critical nodal points to produce down-stream adverse effects. From this knowledge, combinations of chemicals with different mechanisms of action are predicted that should result in cumulative effects. These predictions are then mapped against evidence from experimental mixture studies with relevant combinations. From the outcome of this analysis it is concluded that cumulative assessment groups for male reproductive health risks should not only include phthalates but also comprise androgen receptor (AR) antagonists, chemicals capable of disrupting steroid synthesis, InsL3 production, prostaglandin signalling and co-planar polychlorinated dibenzo-dioxins together with other dioxin-like compounds. This list goes far beyond what has been suggested previously. A minimum set of chemicals to be assessed together with phthalates includes pesticides such as vinclozolin, prochloraz, procymidone, linuron, the pain killers paracetamol, aspirin and ibuprofen, pharmaceuticals such as finasteride, ketoconazole, and the lipid-lowering drug simvastin, poly-chlorinated dibenzo-dioxins and other dioxin-like pollutants and phenolics such as bisphenol A and butylparaben. AOP network analyses are essential to overcome difficulties in establishing groupings of chemicals for mixture risk assessments that derive from a narrow focus on mechanisms and modes of action.

Phthalate exposure and neurodevelopmental outcomes in early school age children from Poland

Some phthalates are known endocrine disrupting chemicals (EDC). They are widely present in the environment thus their impact on children's health is of particular scientific interest. The aim of the study was to evaluate the association between phthalate exposure and neurodevelopmental outcomes, in particular behavioral, cognitive and psychomotor development, in 250 early school age children from the Polish Mother and Child Cohort (REPRO_PL). Urine samples were collected at the time of children's neurodevelopmental assessment and were analysed for 21 metabolites of 11 parent phthalates. Behavioral and emotional problems were assessed by the Strengths and Difficulties Questionnaire (SDQ) filled in by the mothers. To assess children's cognitive and psychomotor development, Polish adaptation of the Intelligence and Development Scales (IDS) was administered. The examination was performed by trained psychologists. Dimethyl phthalate (DMP) and di-n-butyl phthalate (DnBP) were the two phthalates showing the highest statistically significant associations, with higher total difficulties scores (β = 1.5, 95% CI 0.17; 2.7; β = 1.5, 95% CI 0.25; 2.8, respectively) as well as emotional symptoms and hyperactivity/inattention problems for DnBP (β = 0.46, 95% CI -0.024; 0.94; β = 0.72, 95% CI 0.065; 1.4, respectively), and peer relationships problems for DMP (β = 0.37, 95% CI -0.013; 0.76). In addition, DnBP and DMP have been found to be negatively associated with fluid IQ (β = -0.14, 95% CI -0.29; 0.0041) and crystallized IQ (β = -0.16, 95% CI -0.29; -0.025), respectively. In the case of mathematical skills, three phthalates, namely DMP (β = -0.17, 95% CI -0.31; -0.033), DEP (β = -0.16, 95% CI -0.29; -0.018) and DnBP (β = -0.14, 95% CI -0.28; 0.0012), have also shown statistically significant associations. This study indicates that exposure to some phthalates seems to be associated with adverse effects on behavioral and cognitive development of early school age children. Further action including legislation, educational and interventional activities to protect this vulnerable population is still needed.

Exposure to Mixed Phthalates in Czech Preschool and School Children

Knowledge of population exposure to phthalates based on the urinary metabolite levels is of the highest importance for health risk assessment. Such data are scarce in the Czech population. In the study conducted in 2016, six urinary phthalate metabolites were analysed in a total of 370 first morning urine samples of healthy children aged 5 and 9 years, namely mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP), mono(2-ethyl-5-oxohexyl) phthalate (5oxo-MEHP), mono-benzyl phthalate (MBzP), mono-iso-butyl phthalate (MiBP), and mono-n-butyl phthalate (MnBP). The two latter mono-butyl phthalate isoforms dominated among all samples with geometric means of 63.0 µg/L (MnBP) and 44.1 µg/L (MiBP), followed by 5OH-MEHP (20.6 µg/L), 5oxo-MEHP (12.9 µg/L), MBzP (3.65 µg/L), and MEHP (2.31 µg/L). Daily intake (DI) of the parent phthalates was estimated using the creatinine-based model. The highest DI values were found for di-n-butyl phthalate (DnBP) (median 2.5 µg/kg bw/day; 95th percentile 7.8 µg/kg bw/day) and di-2-ethylhexyl phthalate (DEHP) (median 2.3 µg/kg bw/day; 95th percentile 8.9 µg/kg bw/day) in 5-year-old children. The tolerable daily intake (TDI) set by the European Food Safety Authority (EFSA) was exceeded in case of DnBP (in 1% of 9-year-olds and in 3% of 5-year-olds). Exposure risk was assessed based on hazard quotients calculation and cumulative approach for similar health effect. The combined exposure to four phthalates expressed by hazard index (HI) for reprotoxicity revealed exceeding of HI threshold in 14% of 5-year-olds and in 9% of 9-year-olds. These findings strongly support the need to reduce the burden of children by phthalates.