Temporal comparison of PBDEs, OH-PBDEs, PCBs, and OH-PCBs in the serum of second trimester pregnant women recruited from San Francisco General Hospital, California

Association between persistent endocrine-disrupting chemicals (PBDEs, OH-PBDEs, PCBs, and PFASs) and biomarkers of inflammation and cellular aging during pregnancy and postpartum

BACKGROUND

Endocrine-disrupting chemicals (EDCs) can target immune and metabolic pathways. However, few epidemiologic studies have examined the influence of EDCs on measures of inflammation and cellular aging during pregnancy and postpartum.

OBJECTIVE

We investigated associations between prenatal exposures to polybrominated diphenyl ethers (PBDEs), hydroxylated PBDE metabolites (OH-PBDEs), polychlorinated biphenyls (PCBs), and per- and polyfluorochemicals (PFASs) with repeated biomarker measurements of inflammation and cellular aging in women during pregnancy and the postpartum period.

METHODOLOGY

Overweight or obese pregnant women were recruited from the San Francisco Bay area (n = 103) during their first or second trimester of pregnancy. Blood samples were collected from participants at baseline (median 16 weeks gestation) and at three and nine months postpartum. Serum concentrations of PBDEs, OH-PBDEs, PCBs, and PFASs were measured at baseline. Inflammation biomarkers (interleukin 6 [IL-6], interleukin 10 [IL-10], and tumor necrosis factor [TNF-α]) and leukocyte telomere length (LTL), a biomarker of cellular aging, were measured at all three time points. Associations between serum chemical concentrations and repeated measures of IL-6, IL-10, TNF-α, and LTL were examined using linear mixed models. We also examined the potential for effect modification by time (visit) and obesity.

RESULTS

In adjusted models, we observed positive relationships between PBDEs and pro-inflammatory cytokines (IL-6 and TNF-α). A doubling in ∑PBDEs was associated with a 15.26% (95% CI 1.24, 31.22) and 3.74% (95% CI -0.19, 7.82) increase in IL-6 and TNF-α, respectively. Positive associations were also observed for PFASs and IL-6. A two-fold increase in ∑PFASs was associated with a 20.87% (95% CI 3.46, 41.22) increase in IL-6. 5-OHBDE-47 was inversely associated with anti-inflammatory cytokine IL-10. Some EDC-outcome associations, including those of PBDEs with TNF-α, were stronger during pregnancy (compared to three or nine months postpartum) and among obese (compared to overweight) women (p-interaction <0.05).

CONCLUSIONS

These findings suggest that exposure to specific EDCs is associated with increased inflammation among women during pregnancy and the postpartum period. Future studies should replicate these findings in additional study populations and examine the implications of these associations for maternal and child health.

Perinatal exposure to endocrine disrupting compounds and the control of feeding behavior-An overview

Endocrine disrupting compounds (EDC) are ubiquitous environmental contaminants that can interact with steroid and nuclear receptors or alter hormone production. Many studies have reported that perinatal exposure to EDC including bisphenol A, PCB, dioxins, and DDT disrupt energy balance, body weight, adiposity, or glucose homeostasis in rodent offspring. However, little information exists on the effects of perinatal EDC exposure on the control of feeding behaviors and meal pattern (size, frequency, duration), which may contribute to their obesogenic properties. Feeding behaviors are controlled centrally through communication between the hindbrain and hypothalamus with inputs from the emotion and reward centers of the brain and modulated by peripheral hormones like ghrelin and leptin. Discrete hypothalamic nuclei (arcuate nucleus, paraventricular nucleus, lateral and dorsomedial hypothalamus, and ventromedial nucleus) project numerous reciprocal neural connections between each other and to other brain regions including the hindbrain (nucleus tractus solitarius and parabrachial nucleus). Most studies on the effects of perinatal EDC exposure examine simple crude food intake over the course of the experiment or for a short period in adult models. In addition, these studies do not examine EDC's impacts on the feeding neurocircuitry of the hypothalamus-hindbrain, the response to peripheral hormones (leptin, ghrelin, cholecystokinin, etc.) after refeeding, or other feeding behavior paradigms. The purpose of this review is to discuss those few studies that report crude food or energy intake after perinatal EDC exposure and to explore the need for deeper investigations in the hypothalamic-hindbrain neurocircuitry and discrete feeding behaviors.

Exposure to polybrominated diphenyl ethers (PBDEs) and child behavior: Current findings and future directions

Polybrominated diphenyl ethers (PBDEs) are recognized neurotoxicants, but the extent to which PBDEs influence various domains of behavior in children is not fully understood. As such, we reviewed epidemiologic studies published to date to provide an overview of the current state of knowledge on PBDEs' potential role in behavioral development. We identified 19 epidemiologic studies reporting on associations of prenatal and childhood concentrations of PBDEs with behaviors assessed in children from 1 to 12years, including executive function, attention, externalizing and internalizing behaviors, adaptive skills, and social behaviors/Autism Spectrum Disorder (ASD). While the mechanisms of PBDE neurotoxicity in humans are still not clearly elucidated, findings from this review indicate that PBDE exposure during fetal development is associated with impairments in executive function and poorer attentional control in children. Results from large prospective cohorts demonstrate that prenatal and postnatal PBDE exposure adversely impacts externalizing behavior (e.g., hyperactivity and conduct problems). Additional studies are needed to determine whether PBDEs are associated with internalizing problems, adaptive skills, and social behaviors/ASD in children. Future studies will help better understand the potential neurotoxic effects of PBDE exposures during adolescence, possible sex-dependent effects, and the impact of exposure to BDE-209 and alternative flame retardants. Future studies should also examine chemical mixtures to capture real-world exposures when examining PBDEs and their impact on various behavioral domains in the context of multiple chemical exposures.

Organophosphate Flame-Retardants Alter Adult Mouse Homeostasis and Gene Expression in a Sex-Dependent Manner Potentially Through Interactions With ERα

Flame retardants (FRs) such as polybrominated diphenyl ethers and organophosphate FR (OPFR) persist in the environment and interact with multiple nuclear receptors involved in homeostasis, including estrogen receptors (ERs). However, little is known about the effects of FR, especially OPFR, on mammalian neuroendocrine functions. Therefore, we investigated if exposure to FR alters hypothalamic gene expression and whole-animal physiology in adult wild-type (WT) and ERα KO mice. Intact WT and KO males and ovariectomized WT and KO females were orally dosed daily with vehicle (oil), 17α-ethynylestradiol (2.5 μg/kg), 2,2', 4,4-tetrabromodiphenyl ether (BDE-47, 1 or 10 mg/kg), or an OPFR mixture {1 or 10 mg/kg of tris(1, 3-dichloro-2-propyl)phosphate, triphenyl phosphate, and tricresyl phosphate each} for 28 days. Body weight, food intake, body composition, glucose and insulin tolerance, plasma hormone levels, and hypothalamic and liver gene expression were measured. Expression of neuropeptides, receptors, and cation channels was differentially altered between WT males and females. OPFR suppressed body weight and energy intake in males. FR increased fasting glucose levels in males, and BDE-47 augmented glucose clearance in females. Liver gene expression indicated FXR activation by BDE-47 and PXR and CAR activation by OPFR. In males, OPFR increased ghrelin but decreased leptin and insulin independent of body weight. The loss of ERα reduced the effects of both FR on hypothalamic and liver gene expression and plasma hormone levels. The physiological implications are that males are more sensitive than ovariectomized females to OPFR exposure and that these effects are mediated, in part, by ERα.

Polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDE metabolites (OH-PBDEs) in maternal and fetal tissues, and associations with fetal cytochrome P450 gene expression

BACKGROUND

Human fetal exposures to polybrominated diphenyl ethers (PBDEs) and their metabolites (OH-PBDEs) are unique from adults, and in combination with a different metabolic profile, may make fetal development more sensitive to adverse health outcomes from these exposures. However, we lack data to characterize human fetal PBDE exposures and the metabolic factors that can influence these exposures.

OBJECTIVE

We examined differences between 2nd trimester maternal and fetal exposures to PBDEs and OH-PBDEs. We also characterized fetal cytochrome P450 (CYP) mRNA expression and its associations with PBDE exposures.

METHODS

We collected paired samples of maternal serum and fetal liver (n=86) with a subset having matched placenta (n=50). We measured PBDEs, OH-PBDEs, and mRNA expression of CYP genes (e.g. CYP1A1, -2E1, -2J2, -2C9) in all samples. As a sensitivity analysis, we measured PBDEs and OH-PBDEs in umbilical cord serum from a subset (n=22).

RESULTS

BDE-47 was detected in ≥96% of all tissues. Unadjusted ∑PBDEs concentrations were highest in fetal liver (geometric mean (GM)=0.72ng/g), whereas lipid-adjusted concentrations were highest in cord serum (111.12ng/g lipid). In both cases, fetal concentrations were approximately two times higher than maternal serum levels (GM=0.33ng/g or 48.75ng/g lipid). ΣOH-PBDEs were highest in maternal and cord sera and 20-200 times lower than PBDE concentrations. In regression models, maternal BDE-47 explained more of the model variance of liver than of placenta BDE-47 concentrations (adjusted R²=0.79 vs 0.48, respectively). In adjusted logistic regression models, ∑PBDEs were positively associated with expression of CYP2E1 and -2J2 (placenta), and -1A1 (liver) (p<0.05).

CONCLUSION

Our findings suggest that under normal conditions of mid-gestation, the human fetus is directly exposed to concentrations of PBDEs that may be higher than previously estimated based on maternal serum and that these exposures are associated with the expression of mRNAs coding for CYP enzymes. These results will help frame and interpret findings from studies that use maternal or cord blood as proxy measures of fetal exposures, and will inform the molecular pathways by which PBDEs affect human health.

Polybrominated diphenyl ethers (PBDEs) and hydroxylated PBDE metabolites (OH-PBDEs): A six-year temporal trend in Northern California pregnant women

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants. Technical mixtures PentaBDE and OctaBDE were phased out in 2004 through voluntary and regulatory actions with DecaBDE remaining in limited use until 2013. Biomonitoring studies have shown widespread presence of PBDEs in the US and worldwide population. While some studies suggest that human serum concentrations are declining over time, it is unclear whether this trend will continue. Our objective was to examine temporal trends of PentaBDEs and their hydroxylated metabolites (OH-PBDEs) between 2008 and 2014 in populations of ethnically diverse, pregnant women residing in Northern California (n = 111). Serum samples were collected and analyzed by high resolution mass spectrometry for five PentaBDE congeners and two OH-PBDEs. We found widespread exposures in participants from all three time points (2008/09, 2011/12, 2014). Temporal patterns varied substantially by congener. BDE-47, -99 and the OH-PBDEs decreased between 2008/09-2011/12 but plateaued between 2011/12-2014. In contrast, BDE-100 decreased across all years, BDE-153 decreased in the latter years, and BDE-28 decreased initially and then increased. These findings indicate that while policies to remove PBDEs from the marketplace have successfully lead to declines in exposures to some PBDE congeners, human exposures to these legacy pollutants could plateau and remain ubiquitous in human populations.

Associations between serum polybrominated diphenyl ethers and thyroid hormones in a cross sectional study of a remote Alaska Native population

Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental pollutants. Arctic indigenous peoples are exposed to PBDEs through a traditional diet high in marine mammals. PBDEs disrupt thyroid homeostasis. The aim of this study was to assess the relationship between serum PBDEs and thyroid function in a remote population of St. Lawrence Island Yupik. Serum samples were collected from 85 individuals from St. Lawrence Island, Alaska and measured for concentrations of PBDEs, free and total thyroxine (T4), free and total triiodothyronine (T3), and thyroid stimulating hormone (TSH). The relationships between PBDEs and thyroid hormones were assessed using multiple linear regression fit with generalized estimating equations. Serum concentrations of several Penta-BDE congeners (BDE-28/33, 47, and 100) were positively associated with concentrations of TSH and free T3, while serum concentration of BDE-153 was negatively associated with total T3 concentrations. Both BDE-47 and 153 remained significantly associated with thyroid hormones when BDE-47, BDE-153, and BDE-209 were covariates in the same model. There were no significant relationships between serum concentrations of PBDEs and either free or total T4. Individual PBDEs are associated with thyroid hormones in serum from a remote population of Alaska Natives, and directions of effect differ by congener.

Prenatal Serum Concentrations of Brominated Flame Retardants and Autism Spectrum Disorder and Intellectual Disability in the Early Markers of Autism Study: A Population-Based Case-Control Study in California

BACKGROUND

Prior studies suggest neurodevelopmental impacts of polybrominated diphenyl ethers (PBDEs), but few have examined diagnosed developmental disorders.

OBJECTIVES

Our aim was to determine whether prenatal exposure to brominated flame retardants (BFRs) is associated with autism spectrum disorder (ASD) or intellectual disability without autism (ID).

METHODS

We conducted a population-based case-control study including children with ASD (n=545) and ID (n=181) identified from the California Department of Developmental Services and general population (GP) controls (n=418) from state birth certificates. ASD cases were matched to controls by sex, birth month, and birth year. Concentrations of 10 BFRs were measured in maternal second trimester serum samples stored from routine screening. Logistic regression was used to calculate crude and adjusted odds ratios (AOR) for associations with ASD, and separately for ID, compared with GP controls, by quartiles of analyte concentrations in primary analyses.

RESULTS

Geometric mean concentrations of five of the six congeners with ≥55% of samples above the limit of detection were lower in mothers of children with ASD or ID than in controls. In adjusted analyses, inverse associations with several congeners were found for ASD relative to GP (e.g., quartile 4 vs. 1, BDE-153: AOR=0.56, 95% CI: 0.38, 0.84). When stratified by child sex (including 99 females with ASD, 77 with ID, and 73 with GP), estimates were consistent with overall analyses in boys, but in the opposite direction among girls, particularly for BDE-28 and -47 (AOR=2.58, 95% CI: 0.86, 7.79 and AOR=2.64, 95% CI: 0.97, 7.19, respectively). Similar patterns overall and by sex were observed for ID.

CONCLUSIONS

Contrary to expectation, higher PBDE concentrations were associated with decreased odds of ASD and ID, though not in girls. These findings require confirmation but suggest potential sexual dimorphism in associations with prenatal exposure to BFRs. https://doi.org/10.1289/EHP1079.

Perinatal exposure to 2,2',4'4' -Tetrabromodiphenyl ether induces testicular toxicity in adult rats

Since 1965, polybrominated diphenyl ethers (PBDEs) have been used internationally as flame-retardant additives. PBDEs were recently withdrawn from commerce in North America and Europe due to their environmental persistence, bioaccumulative properties and endocrine-disrupting effects. Generations exposed perinatally to the highest environmental doses of PBDE account for one-fifth of the total United States population. While, toxicity of PBDE for the male reproductive system has been demonstrated in several human and animal studies, the long-lasting effects of perinatal exposures on male reproduction are still poorly understood. In this study, pregnant Wistar rats were exposed to 0.2mg/kg 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) from gestation day 8 until postnatal day 21. Male reproductive outcomes were analyzed on postnatal day 120 in offspring. Exposed animals had significantly smaller testes, displayed decreased sperm production per testis weight, had significantly increased percentage of morphologically abnormal spermatozoa, and showed an increase in spermatozoa head size. Perinatal BDE-47 exposure led to significant changes in testes transcriptome, including suppression of genes essential for spermatogenesis and activation of immune response genes. In particular, we observed a 4-fold average decrease in expression of protamine and transition protein genes in testes, suggesting that histone-protamine exchange may be dysregulated during spermatogenesis, resulting in an aberrant sperm epigenome. The possibility of long-lasting effects of developmental PBDE exposures calls for additional studies to build a foundation for the development of preventive and protective interventions against the environmentally-induced decline in fertility.

Temporal trends of lipophilic persistent organic pollutants in serum from Danish nulliparous pregnant women 2011-2013

The use of the lipophilic persistent organic pollutants (POPs) including polychlorinated biphenyls (PCBs) and several organochlorine pesticides (OCPs) has been prohibited for more than 30 years. In this study, we present the temporal trends of the lipophilic POP serum concentrations in Danish nulliparous pregnant women between 2011 and 2013. We randomly selected 197 pregnant women (gestational age 11-13) from the Aarhus Birth Cohort. The concentrations of the lipophilic POPs in the serum samples were analyzed using gas chromatography. The concentrations were corrected for total serum lipids. The statistical analysis was performed by regression analysis with adjustment for age, BMI, gestational age at blood draw, and smoking status. The serum concentrations of PCB 118, 138, 153, 156, 170, 180, 187, and hexachlorobenzen, trans-nonachlor, β-hexachlorocyclohexane (β-HCH), and p,p'-dichlorodiphenyldichloroethylene were lower in 2013 than in 2011. However, the oxychlordane concentration was lowest in 2011. The serum levels of most lipophilic POPs followed downward trends during the study period, which was expected, as these compounds has been banned for many years. The upward trend of oxychlordane was unexpected and presumably a chance finding.

Current halogenated flame retardant concentrations in serum from residents of Shandong Province, China, and temporal changes in the concentrations

The residents of Shandong Province, China, are exposed to high concentrations of halogenated flame retardants because large amounts of halogenated flame retardants are produced in the province. We determined the concentrations of eight polybrominated diphenyl ether congeners (PBDEs), seven novel brominated flame retardants (NBFRs), and the two dechlorane plus isomers (DPs) in serum from residents of Shandong Province. The aim was to identify temporal trends in the concentrations of these pollutants. The mean total concentrations of PBDEs, NBFRs and DPs were 41, 2.2 and 2.1ng/g lipid in pooled serum samples collected in 2014, and were 32, 3.5 and 3.1ng/g lipid in pooled serum samples collected in 2015, respectively. Decabromodiphenyl ether was the dominant PBDE congener in all of the samples. The novel brominated flame retardant and dechlorane plus concentrations were between one and two orders of magnitude lower than the PBDE concentrations. The PBDE concentrations in serum decreased significantly between 2007 and 2015, but the pentabromobenzene, pentabromotoluene, and dechlorane plus concentrations were relatively stable.

Dichloro-diphenyl-trichloroethanes (DDTs) in human hair and serum in rural and urban areas in South China

Human hair has been employed as a biomarker for exposure to persistent organic pollutants (POPs), but information on the source of dichloro-diphenyl-trichloroethane (DDT) and its metabolites in hair is limited. The present study investigated the contamination of DDTs in human hair from a rural area and an urban area of South China and compared with those in human serum and indoor dust. The concentrations of ∑DDTs ranged from 2.30 to 489ng/g, with a median of 21.8ng/g in human hair. The ∑DDT concentrations (median=40.8ng/g) in female hair were significantly higher than those in male hair (median=20.6ng/g). There were significantly positive correlations between the concentrations of DDTs and ages in both the female and male hair, but the age-dependence for DDTs in serum was less significant. The profile of DDT analogues in female hair, differing from that in the male hair, was more similar to that in the indoor dust, suggesting a more important role of exogenous exposure in female hair. We estimated that exogenous source is responsible for approximately 11% and 20% of the burden of DDTs in the male and female hair, respectively. Adjusted multiple linear regression model showed significantly positive association between the p,p'-DDE concentrations in the paired hair and serum samples, indicating that endogenous origins are the primary sources of DDTs in the hair of the residents in the study areas. Our findings demonstrated that human hair is a reliable biomarker for body burden of DDTs and can be used in epidemiology research and retrospective assessment of DDT exposure.

Temporal Evaluation of Polybrominated Diphenyl Ether (PBDE) Serum Levels in Middle-Aged and Older California Women, 2011-2015

In response to health concerns and widespread human exposures, two widely used commercial formulations of polybrominated diphenyl ethers (PBDEs) were banned in the United States in 2005. Initial biomonitoring data have provided early indications of reduced human exposures since these bans took effect. Our objective was to evaluate temporal trends in PBDE serum levels among a population of older California women during a four-year period, beginning approximately five years after these formulations were banned. Automated solid phase extraction and gas chromatography/high resolution mass spectrometry were used to measure PBDE levels in blood collected during 2011-2015 among 1253 women (ages 40-94) participating in the California Teachers Study. Only congeners with detection frequencies (DF) ≥ 75% were included in the present analysis: BDE-47 (DF = 88%); BDE-100 (DF = 78%); and BDE-153 (DF = 80%). Results from age- and race/ethnicity-adjusted linear regression analyses indicated modest, but statistically significant, average annual percent increases in the serum concentrations of all three PBDEs over the four-year study period. While not without limitations, these results, in the context of other biomonitoring data, suggest that earlier reported declines in PBDE levels may have plateaued and may now be starting to increase. Further biomonitoring to ascertain current trends and determinants of population exposures is warranted.

Developmental Exposure to 2,2',4,4'-Tetrabromodiphenyl Ether Induces Long-Lasting Changes in Liver Metabolism in Male Mice

Polybrominated diphenyl ethers (PBDEs) were used as flame-retardant additives in a wide range of polymers. The generations born when environmental concentrations of PBDEs reached their maximum account in the United States for one-fifth of the total population. We hypothesized that exposure to PBDEs during sensitive developmental windows might result in long-lasting changes in liver metabolism. The present study was based on experiments with CD-1 mice and human hepatocellular carcinoma cells (human hepatoma cell line, HepG2). Pregnant mice were exposed to 0.2 mg/kg 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) from gestation day 8 until postnatal day 21. The metabolic health-related outcomes were analyzed on postnatal day 21 and postnatal week 20 in male offspring. Several groups of metabolic genes, including ribosomal and mitochondrial genes, were significantly upregulated in the liver at both points. Genes regulated via mechanistic target of rapamycin (mTOR) pathway, the gatekeeper of metabolic homeostasis, were whether up- or downregulated at both measurement points. On postnatal day 21, but not week 20, both mTOR complexes in the liver were activated, as measured by phosphorylation of their targets. mTOR complexes were also activated by BDE-47 in HepG2 cells in vitro. The following changes were observed at week 20: a decreased number of polyploid hepatocytes, suppressed cytoplasmic S6K1, twofold greater blood insulin-like growth factor-1 and triglycerides, and 2.5-fold lower expression of fatty acid uptake membrane receptor CD36 in liver tissue. Thus, perinatal exposure to environmentally relevant doses of BDE-47 in laboratory mice results in long-lasting changes in liver physiology. Our evidence suggests involvement of the mTOR pathway in the observed metabolic programming of the liver.

Do flame retardant chemicals increase the risk for thyroid dysregulation and cancer?

PURPOSE OF REVIEW

Flame retardant chemicals are added to consumer products to reduce fire incidence and severity; approximately 1.5 million tons of these chemicals are used annually. However, their widespread use has led to their ubiquitous presence in the environment and chronic accumulation in human tissues. We summarize current trends in human flame retardant chemical exposure, and review recent data highlighting concerns for thyroid dysregulation and cancer risk in human populations.

RECENT FINDINGS

Polybrominated diphenyl ethers were once commonly used as flame retardant chemicals, but recently were phased out. Exposure is associated with thyroid dysregulation (mainly T4 reductions) in animals, with new work focusing on specific mechanisms of action. Polybrominated diphenyl ethers also impact human thyroid regulation and are related to clinical thyroid disease, but associations appear both dose and life-stage dependent. Emerging data suggest that common alternate flame retardant chemicals may be more potent thyroid disruptors than their predecessors, which is particularly concerning given increasing levels of exposure.

SUMMARY

Potential health impacts of flame retardant chemicals are only beginning to be understood for 'legacy flame retardant chemicals' (i.e., polybrominated diphenyl ethers), and are largely unevaluated for newer-use chemicals. Cumulatively, current data suggest impact on thyroid regulation is likely, potentially implicating flame retardant chemicals in thyroid disease and cancers for which thyroid dysregulation impacts risk or prognosis.

Determination of hydroxylated polychlorinated biphenyls (OH-PCBs) in human urine in a highly occupationally exposed German cohort: New prospects for urinary biomarkers of PCB exposure

The present study evaluates for the first time the determination of 20 hydroxylated polychlorinated biphenyl (OH-PCB) congeners and their glucuronide and sulfate conjugates in urine as a biomarker of exposure to PCBs in humans. Thereby, a fast, sensitive and selective online solid phase extraction (SPE) method coupled to LC-MS/MS was validated for the determination of OH-PCBs in human urine, being previously successfully developed and applied for the separation and quantitation of OH-PCBs in human plasma. The lowest limit of quantification (LLOQ) ranged from 0.01 to 0.19ngmL^-1 and average extraction recoveries from 79 to 125% for all hydroxylated congeners. Within-run precision and between-run precision were between 2 and 17%. Extraction recovery tests were also performed in urine with different creatinine contents (0.52-3.92gL^-1) for an estimation of matrix influences and ranged between 69 and 125%. In order to evaluate the applicability of the method, the study was conducted in three different groups, which were distinctly separated as non-exposed to known sources of PCBs (N=21), low-to-moderate PCB-exposed individuals (N=25) and highly occupationally PCB-exposed individuals (N=25), which included workers of a transformer recycling plant, their relatives and workers of surrounding companies from a German cohort. As part of the biomonitoring program HELPcB (Health Effects in High-Level Exposure to polychlorinated biphenyls), urine and blood samples were collected annually from 2010 to 2014. In this way, OH-PCB elimination profile in urine over time, correlations between OH-PCB levels in human plasma and urine, and associations with their parent compounds in plasma of the studied PCB cohort could be also assessed. Tri-chlorinated OH-PCBs were the predominant congeners in urine with concentrations up to 174ngmL^-1. High chlorinated OH-PCBs (penta- through hepta-chlorinated OH-PCBs) were also frequently detected in urine samples from non-exposed and occupationally exposed individuals, although levels were in general very low or lower than LLOQ.

Biomarkers of exposure to environmental contaminants in French pregnant women from the Elfe cohort in 2011

BACKGROUND

As part of the perinatal component of the French Human Biomonitoring (HBM) program, biomarkers levels of various chemicals have been described among pregnant women having given birth in continental France in 2011 and who have been enrolled in the Elfe cohort (French Longitudinal Study since Childhood). This paper describes the design of the study and provides main descriptive results regarding exposure biomarkers levels.

METHODS

Exposure biomarkers were measured in biological samples collected at delivery from pregnant women randomly selected among the participants in the clinical and biological component of the Elfe cohort (n=4145). The geometric mean and percentiles of the levels distribution were estimated for each biomarker. The sampling design was taken into account in order to obtain estimates representative of the French pregnant women in 2011.

RESULTS

Results provide a nation-wide representative description of biomarker levels for important environmental contaminants among pregnant women who gave birth in France in 2011. Bisphenol A (BPA), and some metabolites of phthalates, pesticides (mainly pyrethroids), dioxins, furans, polychlorobiphenyls (PCBs), brominated flame retardants (BFRs), perfluorinated compounds (PFCs) and metals (except uranium) were quantified in almost 100% of the pregnant women. Some compounds showed a downward trend compared to previous studies (lead, mercury), but others did not (pyrethroids) and should be further monitored.

CONCLUSION AND PERSPECTIVES

The present results show that French pregnant women are exposed to a wide variety of pollutants, including some that have been banned or restricted in France.

Environmental Chemicals in an Urban Population of Pregnant Women and Their Newborns from San Francisco

Exposures to environmental pollutants in utero may increase the risk of adverse health effects. We measured the concentrations of 59 potentially harmful chemicals in 77 maternal and 65 paired umbilical cord blood samples collected in San Francisco during 2010-2011, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), hydroxylated PBDEs (OH-PBDEs), and perfluorinated compounds (PFCs) in serum and metals in whole blood. Consistent with previous studies, we found evidence that concentrations of mercury (Hg) and lower-brominated PBDEs were often higher in umbilical cord blood or serum than in maternal samples (median cord:maternal ratio > 1), while for most PFCs and lead (Pb), concentrations in cord blood or serum were generally equal to or lower than their maternal pair (median cord:maternal ratio ≤ 1). In contrast to the conclusions of a recent review, we found evidence that several PCBs and OCPs were also often higher in cord than maternal serum (median cord:maternal ratio > 1) when concentrations are assessed on a lipid-adjusted basis. Our findings suggest that for many chemicals, fetuses may experience higher exposures than their mothers and highlight the need to characterize potential health risks and inform policies aimed at reducing sources of exposure.

Environmental influences on reproductive health: the importance of chemical exposures

Chemical exposures during pregnancy can have a profound and life-long impact on human health. Because of the omnipresence of chemicals in our daily life, there is continuous contact with chemicals in food, water, air, and consumer products. Consequently, human biomonitoring studies show that pregnant women around the globe are exposed to a variety of chemicals. In this review we provide a summary of current data on maternal and fetal exposure, as well as health consequences from these exposures. We review several chemical classes, including polychlorinated biphenyls, perfluoroalkyl substances, polybrominated diphenyl ethers, phenols, phthalates, pesticides, and metals. Additionally, we discuss environmental disparities and vulnerable populations, and future research directions. We conclude by providing some recommendations for prevention of chemical exposure and its adverse reproductive health consequences.

Regional comparison of organophosphate flame retardant (PFR) urinary metabolites and tetrabromobenzoic acid (TBBA) in mother-toddler pairs from California and New Jersey

The use of alternative chemical flame retardants in consumer products is increasing as the result of the phase-out of polybrominated diphenyl ethers. Today, the most commonly detected alternatives in residential furniture include the organophosphate flame retardants (PFRs) and the Firemaster (R) 550 mixture (FM550). Urinary levels of dialkyl and diaryl phosphate esters, and 2-ethylhexyl tetrabromobenzoate (EH-TBB) have been used as biomarkers of human exposure to PFRs and FM550, respectively. In a previous study, we demonstrated that toddlers had significantly higher levels of PFRs relative to their mothers in a cohort from New Jersey; however, it is unclear if there are regional differences in exposure. It is possible that exposure to PFRs may be higher in California relative to other US States due to the California flammability standard, as was seen previously observed for PBDEs. In the current study, we examined urinary levels of PFR metabolites and TBBA in 28 mother-child pairs from California, USA, collected in 2015, and compared them with levels measured in our previous study from New Jersey. Urine samples were extracted using solid-phase extraction and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Diphenyl phosphate (DPHP), isopropyl-phenyl phenyl phosphate (ip-PPP), bis(1,3-dichloro-2propyl) phosphate (BDCIPP) and BCIPHIPP conjugates were detected in 100% of mother and child urine samples, while bis(1-chloro-2-propyl) phosphate (BCIPP), tert-butyl-phenyl phenyl phosphate (tb-PPP) and TBBA were detected in < 50% of samples. Interestingly, BCIPHIPP conjugates were detected in 100% of the urine samples, suggesting ubiquitous exposure to the parent compound, tris(1-chloro-2-propyl) phosphate (TCIPP). The current study found significantly higher BDCIPP levels in California toddlers and higher and ip-PPP levels in mothers as compared to the New Jersey cohort, which may be reflective of California's furniture flammability standard. For example, BDCIPP levels in California children were 2.4 times higher than those in New Jersey children. Consistent with our previous work, the current study showed higher PFR and EH-TBB exposure in children, likely due to increased hand-mouth behavior. Children's DPHP and BDCIPP levels, on average, were 5.9 times and 15 times those of their mothers. Positive correlations between paired mothers and their children were shown for DPHP and BCIPHIPP conjugates but not BDCIPP or ip-PPP. In the children, several predictors of hand-mouth behavior were associated with BDCIPP, DPHP and ip-PPP urine levels, but no associations were observed with BCIPHIPP conjugates.

Realist review of policy intervention studies aimed at reducing exposures to environmental hazards in the United States

Background

Exposure to pollution is a significant risk to human health. However few studies have attempted to identify the types of policy interventions that can reduce the health risks of pollution exposure in the United States. The study objective was to conduct a realist review of policy interventions conducted or aimed at reducing chemical exposures in humans or the environment where exposure was measured.

Methods

A systematic literature search identified published articles that assessed policy interventions using exposure data. Two coders independently extracted data from the studies, assessing methods, context, details of interventions, outcomes, and risks of bias. Data were analyzed iteratively and manually to identify the most effective and transferrable types of interventions. The reasons for variability in the success of different interventions were explored.

Results

The review found that regulatory interventions that eliminate point sources of pollution appeared to reduce exposure to environmental hazards. Regular monitoring to provide environmental and human exposure data helped assess compliance with the regulatory standards. Educational and economic interventions were less successful.

Conclusions

Although some types of regulatory interventions appear to reduce exposures, our findings are limited by the nature of existing interventions, the weaknesses of the study designs used in the literature, and the lack of details on implementation. Information on contextual factors that influence implementation would assist with future reviews and could help identify effective interventions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3461-7) contains supplementary material, which is available to authorized users.

Concentrations and distributions of polybrominated diphenyl ethers and novel brominated flame retardants in tree bark and human hair from Yunnan Province, China

The concentrations and distributions of polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) in tree bark and hair samples from the same area in Yunnan Province, China, were determined. The total PBDE and NBFR concentrations in the tree bark samples were 3.8 ng/g lipid weight to 91 ng/g lipid weight and 0.23 ng/g lipid weight to 5.0 ng/g lipid weight, respectively. The total PBDE and NBFR concentrations in the hair samples were 2.1 ng/g dry weight to 14 ng/g dry weight and 0.083 ng/g dry weight to 0.29 ng/g dry weight, respectively. Decabromodiphenyl ether had similar distributions in the tree bark and hair samples, but other PBDE congeners and NBFRs had different distributions in the tree bark and hair samples. External exposure was found to be mainly responsible for the total PBDE and pentabromotoluene concentrations in hair, but both external and internal exposure were responsible for the pentabromophenyl and hexabromobenzene concentrations in hair.

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in paired maternal and neonatal samples from South China: Placental transfer and potential risks

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are attracting more and more attention for the neurodevelopment toxicity effects. We evaluated the concentrations of 15 individual OH-PBDEs and 3 bromophenol (BRP) congeners in 30 mother-newborn paired placenta, breast milk, fetal cord blood, and neonatal urine samples collected from South China. The geometric mean (GM) concentrations of ∑OH-PBDEs were 37.6, 61.3, and 76.8pgg(-1) ww in placenta, breast milk, and cord blood, respectively. The GM concentrations of ∑BRPs were 47.6, 119, and 30.2pgg(-1) ww in placenta, breast milk, and cord blood, respectively. The GM concentrations of ∑OH-PBDEs and ∑BRPs in neonatal urine were 72.0 and 79.8pgml(-1), respectively. Of the 15 OH-PBDE congeners analyzed, the three most frequently detected congeners were 2'-OH-BDE-68 (72.1%), 6-OH-BDE-47 (67.6%), and 2'-OH-BDE-28 (65.8%). The estimated daily intake (EDI) of OH-PBDEs for the breast-fed infants was 9.31±4.00ngkg(-1) bw day. The accumulation of OH-PBDEs in newborns was much lower than the estimated lowest observed-effect concentration (LOEC) of neurotoxicity. The present study provided the first systematic fundamental data that exposure to OH-PBDEs for newborn and their mothers in South China.

Endocrine-Disrupting Chemicals and Reproductive Health

This review discusses the evidence linking industrial chemicals to a variety of health and reproductive outcomes. Industrial chemical production has increased over the past 30 to 40 years. Basic science, animal models, and epidemiologic data suggest that certain chemicals may act as endocrine disruptors (substances that interfere with normal hormonal action) and may play an etiologic role in a number of conditions whose incidence has also increased during this same period. These include low birth weight, gestational diabetes, obesity, certain cancers, certain birth defects, and neurodevelopmental disorders such as attention deficit disorder and autism. In addition, some environmental chemicals may have epigenetic effects, resulting in transgenerational health impacts. The epidemiologic and experimental evidence that links chemicals such as plasticizers (eg, phthalates and phenols), flame retardants, perfluorinated compounds, and pesticides with adverse reproductive health outcomes is reviewed. Women's health care providers are the liaison between scientific research and their patients; they should educate themselves on the significance of environmental toxins to health. They are ideally positioned, not only to counsel and reassure pregnant women, but also to suggest practicable changes in dietary and lifestyle habits to improve their health. Furthermore, women's health care providers should advocate for regulatory changes that protect women and their families from the health effects of environmental toxins.

PBDE flame retardants, thyroid disease, and menopausal status in U.S. women

BACKGROUND

Women have elevated rates of thyroid disease compared to men. Environmental toxicants have been implicated as contributors to this dimorphism, including polybrominated diphenyl ethers (PBDEs), flame retardant chemicals that disrupt thyroid hormone action. PBDEs have also been implicated in the disruption of estrogenic activity, and estrogen levels regulate thyroid hormones. Post-menopausal women may therefore be particularly vulnerable to PBDE induced thyroid effects, given low estrogen reserves. The objective of this study was to test for an association between serum PBDE concentrations and thyroid disease in women from the United States (U.S.), stratified by menopause status.

METHODS

Serum PBDE concentrations (BDEs 47, 99, 100 and 153) from the National Health and Examination Survey (NHANES) and reports on thyroid problems were available in the NHANES 2003-2004 cycle. Odds ratios (ORs) were calculated using multivariate logistic regression models accounting for population-weighted survey techniques and controlling for age, body mass index (BMI), education, smoking, alcohol consumption and thyroid medication. Menopause status was obtained by self-reported absence of menstruation in the previous 12 months and declared menopause.

RESULTS

Women in the highest quartile of serum concentrations for BDEs 47, 99, and 100 had increased odds of currently having thyroid disease (ORs: 1.5, 1.8, 1.5, respectively) compared to the reference group (1st and 2nd quartiles combined); stronger associations were observed when the analysis was restricted to postmenopausal women (ORs: 2.2, 3.6, 2.0, respectively).

CONCLUSION

Exposure to BDEs 47, 99, and 100 is associated with thyroid disease in a national sample of U.S. women, with greater effects observed post-menopause, suggesting that the disruption of thyroid signaling by PBDEs may be enhanced by the altered estrogen levels during menopause.

Cumulative Chemical Exposures During Pregnancy and Early Development

Industrial and consumer product chemicals are widely used, leading to ubiquitous human exposure to the most common classes. Because these chemicals may affect developmental milestones, exposures in pregnant women and developing fetuses are of particular interest. In this review, we discuss the prevalence of chemical exposures in pregnant women, the chemical class-specific relationships between maternal and fetal exposures, and the major sources of exposures for six chemical classes of concern: phthalates, phenols, perfluorinated compounds (PFCs), flame retardants, polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCs). Additionally, we describe the current efforts to characterize cumulative exposures to synthetic chemicals during pregnancy. We conclude by highlighting gaps in the literature and discussing possible applications of the findings to reduce the prevalence of cumulative exposures during pregnancy.

PBDE levels in breast milk are decreasing in California

To assess the efficacy of the bans in reducing PBDE levels, we recruited 67 California first time mothers (sampled during 2009-2012) and collected cord blood at birth (n = 31), breast milk (n = 66) and maternal blood (n = 65) at 3-8 weeks postpartum. Using the same sample extraction procedures and analytical instrumentation method (GC-HRMS), we compared PBDE as well as PCB levels in these breast milk samples to those from our previous study (n = 82, sampled during 2003-2005) and found that the sum of PBDEs over the ∼7 year course declined by 39% (GeoMean = 67.8 ng/g lipid in 2003-2005; 41.5 ng/g lipid in 2009-2012) and that the sum of PCBs declined by 36% (GeoMean = 71.6 ng/g lipid in 2003-2005; 45.7 ng/g lipid in 2009-2012). This supports our earlier finding of a PBDE decline (39%) in blood. We also found that the PBDE concentrations and congener profiles were similar in breast milk and their matched maternal/cord blood: BDE-47 was the dominant congener, followed by BDE-153, -99, and -100. Similar levels and congener profiles of PBDEs in these matrices suggest that they are at equilibrium. Therefore, we propose that maternal serum levels may be used to predict an infant's daily dose of PBDE exposure from breastfeeding when breast milk levels are not available. In addition, our study confirmed that breastfeeding babies are still exposed to high levels of PBDEs, even though PBDE levels are decreasing.

Vitamin C intervention may lower the levels of persistent organic pollutants in blood of healthy women - A pilot study

Emerging evidence suggests that exposure to endocrine-disrupting chemicals including persistent organic pollutants (POPs) such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) has a long term impact on human health. The goal of this pilot study was to test whether antioxidant intervention by vitamin C supplementation may be a remedial approach to decrease body burden of POPs in humans. Using solid phase extraction coupled with a triple quadrupole mass spectrometer and a gas chromatography high resolution mass spectrometry, we measured 18 PCBs, 7 OCPs, and 5 PBDEs in the blood of 15 healthy California women (8 were obese/overweight and 7 had normal weight) before and after 2 months of vitamin C supplementation (1000 mg/day). We observed higher PBDE levels than PCBs and OCPs, but only PCB and OCP levels were strongly and positively correlated with participant's BMI and age. We also found statistically significant decreases in 6 PCBs (PCB-74, PCB-118, PCB-138, PCB-153, PCB-180, and PCB-187), and 2 OCPs (4,4'-DDE, and 4,4'-DDT), but not PBDEs after vitamin C supplementation. Pending confirmation of this pilot finding in a larger study of both sexes, vitamin C intervention may have important public health implications in protecting health by reducing body burdens of POPs.

A review of status of tetrabromobisphenol A (TBBPA) in China

Tetrabromobisphenol A (TBBPA), a currently intensively used brominated flame retardant (BFR), is employed primarily as a reactive flame retardant in printed circuit boards but also has additive applications in several types of polymers. TBBPA is a ubiquitous environmental contaminant that is observed in both abiotic and biotic matrices. This paper summarizes and critically reviews the published scientific data concerning the current pollution status of TBBPA in China. To provide an indication of the seriousness of the pollution levels of TBBPA in China, the data are compared with available existing data from other countries of the world. According to the available data, the sources of TBBPA in China are mainly derived from the primitive e-waste dismantling, TBBPA manufacturing and processing of TBBPA-based materials. The most serious cases of TBBPA pollution in China are in Guiyu, Guangdong (primitive e-waste dismantling site) with concentrations of TBBPA reaching 66,010-95,040 pg m(-3) in air, Shouguang, Shandong (TBBPA manufacturing site) with concentrations of TBBPA reaching 1.64-7758 ng g(-1) dry weight in soil, and Chaohu Lake, Anhui (industry concentration site) with concentrations of TBBPA reaching 850-4870 ng L(-1) in water. In general, China is the most polluted region as affected by TBBPA compared with other countries. The present review preliminarily reveals the research status of TBBPA in China.

Brominated flame retardants (BFRs) in breast milk and associated health risks to nursing infants in Northern Tanzania

The main aim of this study was to assess brominated flame retardants (BFRs) in breast milk in the Northern parts of Tanzania. Ninety-five colostrum samples from healthy, primiparous mothers at Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), (2,3-dibromopropyl) (2,4,6-tribromophenyl) ether (DPTE), pentabromoethylbenzene (PBEB) and 2,3,4,5,6-pentabromotoluene (PBT). The Ʃ7PBDE (BDE 28, 47, 99, 100, 153, 154, 183) ranged from below level of detection (<LOD) to 785ng/g lipid weight (lw). BDE 47, 99, 100 and 153 were the dominating congeners, suggesting recent and ongoing exposure to banned, commercial PentaBDE mixture. A multiple linear regression model revealed that mothers eating clay soil/Pemba during pregnancy had significantly higher levels of BDE 47, 99, 100 and 153 in their breast milk than mothers who did not eat clay soil/Pemba. Infant birth weight and birth length were significantly correlated with the levels of BDE 47, 99, 100 and 153. The estimated daily intake (ng/kg body weight/day) of BDE 47 and 99 exceeded the US EPA Reference doses (RfD) in four and eight mothers, respectively, suggesting a potential health risk to the nursing infants.

Racial/ethnic disparities in environmental endocrine disrupting chemicals and women's reproductive health outcomes: epidemiological examples across the life course

Disparities in women's reproductive health outcomes across the life course have been well-documented. Endocrine disrupting chemicals may be one factor driving disparities, as studies suggest exposure to certain environmental endocrine disrupting chemicals, such as certain phthalates, bisphenol A, parabens and polybrominated diphenyl ethers are higher in non-whites. Yet, a limited amount of research has focused on these chemical exposures as a potential mediator of racial/ethnic differences in women's reproductive health outcomes, such as pubertal development, fibroids, infertility, and pregnancy complications. Given that race/ethnicity is a social construct, the purpose of this review was to present the current state of the literature on racial/ethnic disparities in both environmental endocrine disrupting chemicals, as well as associations between these chemicals and selected women's reproductive health outcomes. Our goal was to evaluate literature from populations based in the United States to: 1) characterize racial/ethnic differences in environmental endocrine disrupting chemicals and 2) systematically review literature on environmental endocrine disrupting chemicals and selected women's health outcomes in populations containing more than one racial/ethnic group. This review highlights the need for future work in determining whether higher exposures to some environmental endocrine disrupting chemicals might partly explain differences in women's reproductive health outcomes in these higher-exposure and high-risk groups.

Concentrations of polybrominated diphenyl ethers (PBDEs) and 2,4,6-tribromophenol in human placental tissues

Legacy environmental contaminants such as polybrominated diphenyl ethers (PBDEs) are widely detected in human tissues. However, few studies have measured PBDEs in placental tissues, and there are no reported measurements of 2,4,6-tribromophenol (2,4,6-TBP) in placental tissues. Measurements of these contaminants are important for understanding potential fetal exposures, as these compounds have been shown to alter thyroid hormone regulation in vitro and in vivo. In this study, we measured a suite of PBDEs and 2,4,6-TBP in 102 human placental tissues collected between 2010 and 2011 in Durham County, North Carolina, USA. The most abundant PBDE congener detected was BDE-47, with a mean concentration of 5.09ng/g lipid (range: 0.12-141ng/g lipid; detection frequency 91%); however, 2,4,6-TBP was ubiquitously detected and present at higher concentrations with a mean concentration of 15.4ng/g lipid (range:1.31-316ng/g lipid; detection frequency 100%). BDE-209 was also detected in more than 50% of the samples, and was significantly associated with 2,4,6-TBP in placental tissues, suggesting they may have a similar source, or that 2,4,6-TBP may be a degradation product of BDE-209. Interestingly, BDE-209 and 2,4,6-TBP were negatively associated with age (rs=-0.16; p=0.10 and rs=-0.17; p=0.08, respectively). The results of this work indicate that PBDEs and 2,4,6-TBP bioaccumulate in human placenta tissue and likely contribute to prenatal exposures to these environmental contaminants. Future studies are needed to determine if these joint exposures are associated with any adverse health measures in infants and children.

Development of an analytical method to quantify PBDEs, OH-BDEs, HBCDs, 2,4,6-TBP, EH-TBB, and BEH-TEBP in human serum

Polybrominated diphenyl ethers (PBDEs) flame retardants (FRs) were phased-out in the mid-2000s (penta- and octaBDE) and 2013 (decaBDE); however, their hydroxylated metabolites (OH-BDEs) are still commonly detected in human serum. Today, novel FRs such as Firemaster® 550, a mixture that contains two brominated compounds, EH-TBB and BEH-TEBP are used as replacements for PBDEs in some applications, and there is a need to develop a comprehensive analytical method to assess exposure to both legacy PBDEs and novel FRs. This study developed a solid-phase extraction (SPE)-based method to analyze PBDEs, OH-BDEs, 2,4,6-tribromophenol (TBP), hexabromocylcododecane isomers (HBCDs), EH-TBB, and BEH-TEBP in human serum. Briefly, serum proteins were first denatured with formic acid, and then the target analytes were isolated using a SPE column. Finally, the extract was cleaned and fractioned using a silica SPE column. Method performance was assessed by spiking fetal bovine serum with 1-2 ng of the target analytes, and method accuracy was quantified by comparison to a serum Standard Reference Material (SRM). The developed method showed good recovery and accuracy for all target analytes with the exception of the very low and very high molecular weight PBDE congeners. Using this method, 43 serum samples collected from the Healthy Pregnancy, Healthy Baby Study (HPHB) cohort in Durham, NC, USA were analyzed for FRs. A novel finding was the ubiquitous detection of 2,4,6-TBP, at levels greater than the individual PBDE congeners. Furthermore, 2,4,6-TBP was positively correlated with PBDEs, suggesting that they may have a similar source of exposure, or that 2,4,6-TBP may result from metabolism of PBDEs in vivo.

Temporal Changes of PBDE Levels in California House Cats and a Link to Cat Hyperthyroidism

In this study, we measured serum PBDE levels in California (CA) house cats during two time periods: 2008-2010 and 2012-2013 to assess the impacts of the decline in use of these materials after the bans. The median ∑19PBDE level in CA household cats (age ≥10 yr) was 3479 ng/g lipid in 2008-2010 (1st time period, n = 21) and 1518 ng/g lipid in 2012-2013 (2nd time period, n = 22), about 2 times lower than in the first time period (p = 0.006). In contrast, PCB and OCP levels showed no statistically significant changes. With better matched group size and age (HT = 11 vs non-HT = 11, age ≥10 yr) in the second time period, we found that ∑19PBDE level (mean ± SE ng/g lipid) was significantly higher in the HT group (3906 ± 1442) than those in the non-HT group (1125 ± 244) (p = 0.0030). Higher levels of PCBs and OCPs were also found in HT group. Despite the declines of PBDE levels, our findings indicate that the current levels of PBDEs, as well as PCBs and OCPs, may still pose health effects for house cats and, possibly, humans.

Polychlorinated Biphenyls (PCBs) in Human Hair and Serum from E-Waste Recycling Workers in Southern China: Concentrations, Chiral Signatures, Correlations, and Source Identification

Hair is increasingly used as a biomarker for human exposure to persistent organic pollutants (POPs). However, the internal and external sources of hair POPs remain a controversial issue. This study analyzed polychlorinated biphenyls (PCBs) in human hair and serum from electronic waste recycling workers. The median concentrations were 894 ng/g and 2868 ng/g lipid in hair and serum, respectively. The PCB concentrations in male and female serum were similar, while concentrations in male hair were significantly lower than in female hair. Significant correlations between the hair and serum PCB levels and congener profiles suggest that air is the predominant PCB source in hair and that hair and blood PCB levels are largely dependent on recent accumulation. The PCB95, 132, and 183 chiral signatures in serum were significantly nonracemic, with mean enantiomer fractions (EFs) of 0.440-0.693. Nevertheless, the hair EFs were essentially racemic (mean EFs = 0.495-0.503). Source apportionment using the Chemical Mass Balance model also indicated primary external PCB sources in human hair from the study area. Air, blood, and indoor dust are responsible for, on average, 64.2%, 27.2%, and 8.79% of the hair PCBs, respectively. This study evidenced that hair is a reliable matrix for monitoring human POP exposure.

Dietary Exposure to Individual Polybrominated Diphenyl Ether Congeners BDE-47 and BDE-99 Alters Innate Immunity and Disease Susceptibility in Juvenile Chinook Salmon

Polybrominated diphenyl ethers (PBDEs), used as commercial flame-retardants, are bioaccumulating in threatened Pacific salmon. However, little is known of PBDE effects on critical physiological functions required for optimal health and survival. BDE-47 and BDE-99 are the predominant PBDE congeners found in Chinook salmon collected from the Pacific Northwest. In the present study, both innate immunity (phagocytosis and production of superoxide anion) and pathogen challenge were used to evaluate health and survival in groups of juvenile Chinook salmon exposed orally to either BDE-47 or BDE-99 at environmentally relevant concentrations. Head kidney macrophages from Chinook salmon exposed to BDE-99, but not those exposed to BDE-47, were found to have a reduced ability in vitro to engulf foreign particles. However, both congeners increased the in vitro production of superoxide anion in head kidney macrophages. Salmon exposed to either congener had reduced survival during challenge with the pathogenic marine bacteria Listonella anguillarum. The concentration response curves generated for these end points were nonmonotonic and demonstrated a requirement for using multiple environmentally relevant PBDE concentrations for effect studies. Consequently, predicting risk from toxicity reference values traditionally generated with monotonic concentration responses may underestimate PBDE effect on critical physiological functions required for optimal health and survival in salmon.

High exposure of California firefighters to polybrominated diphenyl ethers

Concern about persistent organic pollutants (POPs) in Californians prompted the state's biomonitoring program to conduct a study in firefighters, who are occupationally exposed to high levels of POPs. In this work we present serum concentrations of several classes of POPs (polybrominated diphenyl ethers [PBDEs], polychlorinated biphenyls [PCBs], and organochlorine pesticides [OCPs]) in 101 Southern California firefighters. Despite recently reported declining trends of PBDEs in Californians, high levels were measured in firefighters' serum (Σ5PBDEs: median = 59.1 ng/(g of lipid); range = 18.8-714 ng/(g of lipid)) in comparison to other populations in California during the same period. In addition, nearly one-third of subjects had particularly high serum levels of decabromodiphenyl ether (BDE-209), consistent with other recent results in firefighters; this pattern may be a marker of recent firefighting activity. In contrast, serum levels of PCBs and OCPs measured in firefighters' sera were not elevated compared to U.S. levels. Multivariable analysis indicated that lower levels of serum PBDEs were associated with turnout gear cleaning and storage practices after fires. Our study supports the hypothesis that firefighting activities are likely to increase exposure to PBDEs and that good housekeeping and personal hygiene practices may reduce exposure to these compounds.

Concentrations of persistent organic pollutants in California women's serum and residential dust

BACKGROUND

Humans are exposed to persistent organic pollutants (POPs) through various routes, including consumption of contaminated food and accidental ingestion of settled dust.

OBJECTIVES

We aimed to identify key routes of exposure to organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in California women of reproductive age.

METHODS

Blood was collected from 48 mothers participating in the California Childhood Leukemia Study from 2006 to 2007 and analyzed for POPs using gas chromatography-mass spectrometry. Multivariable linear regression models of natural-log transformed serum concentrations were used to identify determinants of exposure from available questionnaire information on dietary habits, reproductive history, and demographic characteristics, as well as vacuum cleaner dust-POP levels.

RESULTS

After adjusting for blood lipid levels, age, body mass index, cumulative lactation, and sampling date, serum concentrations of multiple major PCBs were positively associated with fish consumption, but not dust-PCB levels. After adjusting for blood lipid levels, Hispanic ethnicity, country of origin, and household annual income, serum concentrations of multiple major PBDEs were positively associated with dust-PBDE levels.

CONCLUSIONS

Our findings suggest that the relative contribution of specific exposure routes to total POP intake varies by chemical class, with dust being a relatively important source of PBDEs and diet being a relatively important source of PCBs.

Hair as a biomarker of systemic exposure to polybrominated diphenyl ethers

The efficacy of using hair as a biomarker for exposure to polybrominated diphenyl ether (PBDE) flame retardants was assessed in humans and an animal model. Paired human hair and serum samples were obtained from adult men and women (n = 50). In parallel, hair, serum, liver, and fat were collected from adult male Sprague-Dawley rats exposed to increasing doses of the PBDE mixture found in house dust for 70 days via the diet. All samples were analyzed by GC-MS for eight common PBDEs: BDE-28, -47, -99, -100, -153, -154, -183, and -209. Paired human hair and serum samples had five congeners (BDE-28, -47, -99, -100, and -154) with significant individual correlations (0.345-0.566). In rat samples, BDE-28 and BDE-183 were frequently below the level of detection. Significant correlations were observed for BDE-47, -99, -100, -153, -154, and -209 in rat hair, serum, liver, and fat across doses, with r values ranging from 0.803 to 0.988; weaker correlations were observed between hair and other tissues when data from the lowest dose group or for BDE-209 were analyzed. Thus, human and rat hair PBDE measurements correlate strongly with those in alternative matrices, validating the use of hair as a noninvasive biomarker of long-term PBDE exposure.

Temporal variability of polybrominated diphenyl ether (PBDE) serum concentrations over one year

Polybrominated diphenyl ethers (PBDEs) are flame retardant chemicals used in consumer products. They are common contaminants in human serum and associated with adverse health effects. Our objectives were to characterize PBDE serum concentrations in a New England cohort and assess temporal variability of this exposure biomarker over a one-year period. We collected three repeated measurements at six-month intervals from 52 office workers from the greater Boston (MA, United States) area from 2010 to 2011. The intraclass correlation coefficient for BDEs 28, 47, 99, 100, and 153 ranged from 0.87 to 0.99, indicating that a single serum measurement can reliably estimate exposure over a one-year period. This was true for both lipid adjusted and nonlipid adjusted concentrations. The kappa statistics, quantifying the level of agreement of categorical exposure classification, based on medians, tertiles, or quartiles ranged from 0.67 to 0.90. Some congeners showed nonsignificant increases from sampling round 1 (winter) to round 2 (summer) and significant decreases from round 2 to round 3 (winter). This study highlights the high reliability of a single serum PBDE measurement for use in human epidemiologic studies.

Polybrominated diphenyl ethers (PBDEs) in human samples of mother-newborn pairs in South China and their placental transfer characteristics

There are limited data concerning the placenta transfer characteristics and accumulation of polybrominated diphenyl ethers (PBDEs) in infants. However, PBDEs received increasing health concerns due to their endocrine disrupt and neurodevelopment toxicity effects. The present study assessed the accumulation of PBDEs in 30 paired placenta, breast milk, fetal cord blood, and neonatal urine samples collected from five major cities of the South China. The age of mothers ranged from 21 to 39 (mean 27.6±4.56). The ∑PBDE concentrations were 15.8±9.88 ng g(-1) lipid in placenta, 13.2±7.64 ng g(-1) lipid in breast milk, 16.5±19.5 ng g(-1) lipid in fetal cord blood, and 1.80±1.99 ng ml(-1) in neonatal urine. BDE-47 was the predominant congener in all types of human sample. Octa-BDEs such as BDE-196/-197 were detected highly in placenta and cord blood while moderately in breast milk and neonatal urine. Significant (p<0.01) correlations were observed for both total and most individual PBDEs in cord blood-maternal placenta and breast milk-urine paired individual samples. The extent of placental transfer of higher brominated BDEs such as BDE-196/-197 was greater than that of BDE-47. The estimated daily intake (EDI) analysis for breast-fed infants revealed that newborns in these areas were exposed to relatively high levels of PBDEs via breast milk. Our study not only provided systematic fundamental data for PBDE distribution but also revealed the placenta transfer characteristics of PBDE congeners in South China.

Variability in PCB and OH-PCB serum levels in children and their mothers in urban and rural U.S. communities

Environmental exposures that affect accumulation of polychlorinated biphenyls (PCBs) in humans are complex and not fully understood. One challenge in linking environmental exposure to accumulation is determining variability of PCB concentrations in samples collected from the same person at different times. We hypothesized that PCBs in human blood serum are consistent from year to year in people who live in the same environment between sampling. We analyzed blood serum from children and their mothers from urban and rural U.S. communities (n = 200) for all 209 PCBs (median ∑PCBs = 45 ng/g lw) and 12 hydroxylated PCBs (median ∑OH-PCBs = 0.09 ng/g fw). A subset of these participants (n = 155) also had blood PCB and OH-PCB concentrations analyzed during the previous calendar year. Although many participants had similar levels of PCBs and OH-PCBs in their blood from one year to the next, some participants had surprisingly different levels. Year-to-year variability in ∑PCBs ranged from -87% to 567% and in ∑OH-PCBs ranged from -51 to 358% (5th-95th percentile). This is the first study to report variability of all PCBs and major metabolites in two generations of people and suggests short-term exposures to PCBs may be a significant component of what is measured in human serum.