A Review of Biomonitoring of Phthalate Exposures

Multiple Stressor Effects of Radon and Phthalates in Children: Background Information and Future Research

The present paper reviews available background information for studying multiple stressor effects of radon (222Rn) and phthalates in children and provides insights on future directions. In realistic situations, living organisms are collectively subjected to many environmental stressors, with the resultant effects being referred to as multiple stressor effects. Radon is a naturally occurring radioactive gas that can lead to lung cancers. On the other hand, phthalates are semi-volatile organic compounds widely applied as plasticizers to provide flexibility to plastic in consumer products. Links of phthalates to various health effects have been reported, including allergy and asthma. In the present review, the focus on indoor contaminants was due to their higher concentrations and to the higher indoor occupancy factor, while the focus on the pediatric population was due to their inherent sensitivity and their spending more time close to the floor. Two main future directions in studying multiple stressor effects of radon and phthalates in children were proposed. The first one was on computational modeling and micro-dosimetric studies, and the second one was on biological studies. In particular, dose-response relationship and effect-specific models for combined exposures to radon and phthalates would be necessary. The ideas and methodology behind such proposed research work are also applicable to studies on multiple stressor effects of collective exposures to other significant airborne contaminants, and to population groups other than children.

Phthalates, bisphenols, parabens, and triclocarban in feminine hygiene products from the United States and their implications for human exposure

Feminine hygiene products, a category of daily necessities, can be a source of exposure to plasticizers and antimicrobial agents in women. Nevertheless, studies on the occurrence of chemicals in feminine hygiene products have received little attention. In this study, 24 endocrine-disrupting chemicals (EDCs), comprising nine phthalates, six parabens, eight bisphenols, and triclocarban (TCC) were measured in seven categories of feminine hygiene products (i.e., pads, panty liners, tampons, wipes, bactericidal creams and solutions, and deodorant sprays and powders; N = 77) collected in the Albany area of New York State in the United States. Dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di-iso-butyl phthalate (DIBP), di(2-ethylhexyl) phthalate (DEHP), methyl paraben (MeP), and ethyl paraben (EtP) were found in all pad, panty liner, and tampon samples. Panty liners contained the highest concentrations of DMP (median: 249 ng/g), DEP (386 ng/g), DBP (393 ng/g), and DIBP (299 ng/g) and tampons contained the highest concentrations of DEHP (267 ng/g). MeP, EtP, and propyl paraben (PrP) were the major parabens found in feminine hygiene products. Bactericidal creams and solutions contained median concentrations of MeP, EtP and PrP at 2840, 734, and 278 ng/g, respectively. The estimated exposure doses of phthalates, parabens, and bisphenols through the dermal absorption pathway from the use of pads, panty liners, and tampons were significant. In comparison with the exposure doses reported previously from other sources and pathways, the significance of feminine hygiene products as sources of EDC exposure was delineated. The dermal absorption doses from the use of feminine hygiene products, under different exposure scenarios, were 0.19-27.9% and 0.01-6.2% of the total exposure doses of phthalates and bisphenols, respectively. This is the first study to report the occurrence of phthalates, parabens, bisphenols, and TCC in feminine hygiene products from the United States.

Di-(2-ethylhexyl) Phthalate (DEHP) and Uterine Histological Characteristics

Phthalates have a long industrial history. It is suspected that phthalates and their metabolites have detrimental effects on reproduction and development. They are well-known for their anti-androgenic effects. Several studies have indicated that phthalates and their metabolites are reprotoxic in males and endocrine disruptors. Reproduction and embryogenesis occur in the uterus of female eutherian mammals. A horizontal analytical method is preferred to elucidate the toxic effects of phthalates on human reproduction. Nevertheless, there are vast numbers of known phthalates and not all of their modes of action have been clarified. Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer and has been the subject of numerous toxicological studies. However, few of these have reported on the toxic effects of DEHP, its metabolites, other phthalates, or mixtures on female reproduction. Acute and high doses of DEHP adversely affect uterine histology. Recently, it was disclosed that chronic exposures to low doses of DEHP have endocrine disruption efficacy. DEHP induces various cellular responses including modulation of the expression and regulation of steroid hormone receptors and transcription and paracrine factors. Uteri do not respond uniformly to DEHP exposure. The phenotypic manifestations and effects on fertility in response to DEHP and its metabolites may vary with species, developmental stage, and generation. Hence, DEHP exposure may histological alter the uterus and induce endometriosis, endometriosis, hyperplasia, myoma, and developmental and reproductive toxicity.

Bisphenol A and Phthalates in Diet: An Emerging Link with Pregnancy Complications

Endocrine-disrupting chemicals (EDCs) are exogenous substances that are able to interfere with hormone action, likely contributing to the development of several endocrine and metabolic diseases. Among them, Bisphenol A (BPA) and phthalates contaminate food and water and have been largely studied as obesogenic agents. They might contribute to weight gain, insulin resistance and pancreatic β-cell dysfunction in pregnancy, potentially playing a role in the development of pregnancy complications, such as gestational diabetes mellitus (GDM), and adverse outcomes. Pregnancy and childhood are sensitive windows of susceptibility, and, although with not univocal results, preclinical and clinical studies have suggested that exposure to BPA and phthalates at these stages of life might have an impact on the development of metabolic diseases even many years later. The molecular mechanisms underlying this association are largely unknown, but adipocyte and pancreatic β-cell dysfunction are suspected to be involved. Remarkably, transgenerational damage has been observed, which might be explained by epigenetic changes. Further research is needed to address knowledge gaps and to provide preventive measure to limit health risks connected with exposure to EDCs.

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

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

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

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

Urinary concentrations and distribution profiles of 21 phthalate metabolites in pet cats and dogs

Phthalates are widely used in several consumer products, including plastics, toys, cosmetics, and medical devices. Little is known about phthalate exposure in pet animals, however, even though they share an indoor environment with humans; this is the first study to measure such exposure. We measured 21 phthalate monoester metabolites (PhMs) in the urine of pet cats (n = 50) and dogs (n = 50) collected from New York State, USA. PhMs were widely detected in all samples, and 12 of 21 PhMs had detection frequencies (Dfs) >80%. The median urinary concentrations of total PhMs in pet cats and dogs were 630 ng/mL and 186 ng/mL, respectively. Monoethyl phthalate (mEP) was the most abundant compound in both cats and dogs. Phthalic acid (PA; a non-specific metabolite of phthalates) was found at very high concentrations in cats (median: 520 ng/mL). The estimated daily intake (EDI) and hazard quotient (HQ) for major phthalates in pets showed that DEHP exposures in cats and dogs were only 2-fold less than the US Environmental Protection Agency suggested reference dose (RfD) for humans.

Phthalate Metabolites, Hydroxy-Polycyclic Aromatic Hydrocarbons, and Bisphenol Analogues in Bovine Urine Collected from China, India, and the United States

Human exposure to endocrine-disrupting chemicals (EDCs) has aroused considerable public concern over the last three decades. Nevertheless, little is known with regard to the exposure of EDCs in farm animals. In this study, concentrations of 22 phthalate metabolites (PhMs), 15 hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), and 8 bisphenols (BPs) were determined in 183 bovine urine samples collected from China, India, and the United States. The median concentrations of urinary PhMs, OH-PAHs, and BPs in bovines, collectively, were 66, 4.6, and 16 ng/mL, respectively. Mono-n-butyl phthalate (mBP; median, 14 ng/mL) and ∑₄DEHP (four secondary metabolites of di(2-ethylhexyl) phthalate; 13 ng/mL) were the dominant PhMs; hydroxy-fluorene (OH-Fluo; 1.2 ng/mL) and -phenanthrene (OH-Phen; 1 ng/mL) were the dominant OH-PAHs; and 4,4'-di-hydroxydiphenylmethane (BPF; 10 ng/mL) and 2,2-bis(4-hydroxyphenyl) propane (BPA; 6.7 ng/mL) were the dominant BPs. Bovine urine samples from India and China contained the highest concentrations of PhMs and OH-PAHs, whereas those from India and the United States contained the highest concentrations of BPs. PhM and OH-PAH concentrations were significantly higher in the urine of bulls than those of cows; no such difference was found for BPs. Our findings establish baseline exposure information about three classes of EDCs in domestic farm animals.