Brominated and fluorinated organic pollutants in the breast milk of first-time Irish mothers: is there a relationship to levels in food?

Novel halogenated flame retardants in Canadian human milk from the MIREC study (2008-2011)

Novel halogenated flame retardants (NHFRs) have been developed to replace those brominated flame retardants that have been restricted due to their persistence, bioaccumulation potential and toxicity, therefore, it is important to determine whether these replacement products are present at detectable concentrations in Canadians. NHFRs were measured in human milk samples (n = 541) collected from across Canada between 2008 and 2011, which is the first pan-Canadian dataset for these chemicals in human milk. Among the 15 measured NHFRs and eight methoxy-polybrominated diphenyl ethers (MeO-PBDEs), nine NHFRs and two MeO-PBDEs (6-MeO-PBDE 47 and 2-MeO-PBDE 68) were detected at a frequency of more than 9%. Despite benzene, 1,1'-(1,2-ethanediyl)bis [2,3,4,5,6-pentabromo-]/decabromodiphenylethane [DBDPE] being detected less frequently than the other observed NHFRs, its relative contribution to the sum of nine NHFRs was important when it was present. The maximum ΣNHFR concentration in Canadian human milk was 6930 pg g-1 lipid while the maximum ΣMeO-PBDEs was 1600 pg g-1 lipid. While most NHFR concentrations were significantly correlated with each other, no relationships between maternal age, parity or pre-pregnancy BMI were identified with ΣNHFR concentrations in the milk. In contrast, maternal age was significantly correlated with ΣMeO-PBDE concentrations (r = 0.237, p < 0.001). ΣNHFR concentrations were similarly not related to maternal education, although ΣMeO-PBDE concentrations were found to be higher in milk from women who had graduated from trade schools relative to the other education levels considered. NHFR detection frequency and concentrations observed in the Canadian human milk seem to align well with Europe.

Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food

The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.

Has Regulatory Action Reduced Human Exposure to Flame Retardants?

Flame retardant (FR) exposure has been linked to several environmental and human health effects. Because of this, the production and use of several FRs are regulated globally. We reviewed the available records of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDDs) in human breast milk from literature to evaluate the efficacy of regulation to reduce the exposure of FRs to humans. Two-hundred and seven studies were used for analyses to determine the spatial and temporal trends of FR exposure. North America consistently had the highest concentrations of PBDEs, while Asia and Oceania dominated HBCDD exposure. BDE-49 and -99 indicated decreasing temporal trends in most regions. BDE-153, with a longer half-life than the aforementioned isomers, typically exhibited a plateau in breast milk levels. No conclusive trend could be established for HBCDD, and insufficient information was available to determine a temporal trend for BDE-209. Breakpoint analyses indicated a significant decrease in BDE-47 and -99 in Europe around the time that regulation has been implemented, suggesting a positive effect of regulation on FR exposure. However, very few studies have been conducted globally (specifically in North America) after 2013, during the time when the most recent regulations have been implemented. This meta-analysis provides insight into global trends in human exposure to PBDEs and HBCDD, but the remaining uncertainty highlights the need for ongoing evaluation and monitoring, even after a compound group is regulated.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) in human breast milk from Colombia: A probabilistic risk assessment approach

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) are ubiquitous environmental contaminants. They were produced in relatively large volumes in the last century and are now subject to long-term monitoring and regulated under the United Nations Stockholm Convention (SC) on persistent organic pollutants (POPs). Though restricted, human exposure is still a concern and in some regions of the globe the information on the health risk is limited. Sixty breast milk samples from nursing mothers were collected between 2014 and 2015, residing in Bogota, Cartagena, and Medellin, which are industrialized cities in Colombia. This is the first comprehensive study to determine the concentrations in breast milk of PBDEs (n = 7), PCBs (n = 29), and OCPs (n = 28) in Colombia. The detection frequency of POPs, including BDE-47, CB-138, CB-153, CB-156, and CB-180, as well as several OCPs such as chloroneb, aldrins, HCHs, DDTs, and heptachlor, was found to be 100% in all samples tested. The mean concentrations of the analyzed legacy POPs were ∑3DDTs (423 ng/g lw) > chloroneb (50.1 ng/g lw) > ∑2permetrins (17.5 ng/g lw) > ∑2aldrins (16.7 ng/g lw) > 29 PCBs (15.04 ng/g lw) > ∑2chlordanes (CHLs) (11.2 ng/g lw) ≈ ∑3endosulfans (11.1 ng/g lw) > ∑2heptachlors (2.43 ng/g lw) > 7PBDEs (2.1 ng/g lw) > ∑4HCHs (0.58 ng/g lw). The results of this study suggest that the concentrations of DDTs were present in breast milk samples from Colombia at levels comparable to those found in previous studies conducted in other countries such as Brazil, Uruguay, Chile, and various Asian countries. The concentrations of PBDE and PCB congeners, as well as many pesticides, were found to be significantly correlated with each other. This suggests that these substances may have similar sources of exposure. The strength of the pair correlation among concentrations of POPs was assessed using Spearman's correlation coefficients, which varied from r = 0.62 for the association between BDE-47 and CB-153, to a high correlation of 0.99 for the correlation between γ-Chlordane and heptachlor. This suggests that these POPs may share similar sources, such as diet. An exposure assessment model obtained by Monte Carlo simulation showed that infants were exposed to low concentrations of POPs with exception of p,p'-DDE and Aldrin, in which 25th, 50th and 95th percentiles were greater than the threshold reference values of non-carcinogenic effects suggested by US-EPA regulations while the 90th percentile of pg TEQ/Kg-bw/day for dl-PCBs was above of the tolerable daily intake (TDI) proposed by the World Health Organization (WHO). Therefore, the health risk of infants exposed to OCPs and dl-PCBs should be exanimated continually through biomonitoring programs in the Colombian population.

Contamination characteristics and potential health risk of brominated flame retardants in paddy soils and rice plants around a typical e-waste recycling site in south China

Brominated flame retardants (BFRs) are widely used in various productions. As typical BFRs, polybrominated diphenyl ethers (PBDEs) are prohibited because of their toxicity and persistence. Some of the alternatives to PBDEs, new brominated flame retardants (NBFRs), have also been found in the environment and some have assigned hazardous properties and were categorized as persistent. In this study, a typical e-waste dismantling area was chosen as the study area, and the soil and rice samples were collected from the paddy fields around the circular economy park in Guiyu, China. The contaminations of PBDEs and NBFRs in soils and rice plants were detected, and the health risks associated with consumption and exposure to the environment were calculated as well. The concentrations of ∑PBDEs and ∑NBFRs in soil ranged from 283 to 928 μg/kg and 54.7-437 μg/kg, respectively. In rice plants, the majority of BFRs were concentrated in the following order: root > leaf > stem > grain. Additionally, only the PBT exhibited a stronger bioaccumulation ability in rice with the bioconcentration factors more than 1.00. The results of the health quotient calculation shown that BDE-47 might have an impact on people's health that only the HQ of BDE-47 in the soil was higher than 1.00, while there had no significant health risk in grain of BFRs. We believe that our work could assist researchers in investigating and revealing the human health effects of BFRs in soil and rice.

Assessment of organohalogenated pollutants in breast milk from the Czech Republic

This biomonitoring survey brings new information on the occurrence of a total of 94 organohalogenated pollutants in 231 human breast milk samples collected in 2019 and 2021 from women living in two regions of the Czech Republic (Karvina and Ceske Budejovice). This study aimed to evaluate the concentrations of 6 indicator polychlorinated biphenyls (PCBs), 10 organochlorine pesticides (OCPs), 34 halogenated flame retardants (HFRs), 29 perfluoroalkyl and polyfluoroalkyl substances (PFAS) and 15 polychlorinated naphthalenes (PCNs). PCBs, OCPs, most of HFRs and PCNs were identified/quantified by gas chromatography coupled to (tandem) mass spectrometry (GC-MS(/MS)), while PFAS, hexabromocyclododecane isomers (HBCD), brominated phenols, and tetrabromobisphenol A (TBBPA) by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The mean value of the sum of the 6 indicator PCBs was 123.12 nanogram per gram of lipid weight (ng g^-1 lw). Hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH) and p,p'-dichlorodiphenyl-dichloroethylene (p,p'-DDE) were the most abundant OCPs, detected in 100 % (mean 11.8 ng g^-1 lw), 94.8 % (mean 6.1 ng g^-1 lw) and 100 % (mean 101.5 ng g^-1 lw) of samples, respectively. PCN congeners 20, 52 and 66 were detected in <1 % of the samples. The HFRs concentrations were relatively low compared to the levels of OCP; The detection rate of polybrominated diphenyl ethers (PBDEs, # 47, 99 and 153) ranged 21-68 % with a mean concentrations of 0.34 ng g^-1 lw - 0.42 ng g^-1 lw. PFAS concentrations were also low, with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) dominant in this group (means of 22 pg ml^-1 and 21 pg ml^-1, respectively). Our results confirmed the long-term trend of declining levels of banned POPs in Czech mothers. The amounts of PCBs and OCPs were higher in older breastfeeding primiparous women.

Polychlorinated naphthalenes in milk-based infant and toddler formula sold on the Chinese market

Polychlorinated naphthalenes (PCNs) are dioxin-like compounds that have been reported to be present in a wide variety of foodstuffs. Milk-based infant and toddler formula sometimes plays an important role in the diet of young children and could potentially cause adverse effects if contaminated with PCNs. This study investigated the concentrations of PCNs in commercial milk-based formula produced in different countries and sold on the Chinese market for three age groups: 0-6, 6-12 and 12-36 months. The total concentrations of PCNs in 72 samples from different countries of formula based on cow milk ranged from 7.8 to 30.3 pg/g whole weight (ww). Although the PCN concentrations in formula produced in Asia, Europe and South Pacific varied, all had comparable toxic equivalent (TEQ) values. Tri-CNs were the predominant PCN homologue in all samples. No significant differences in the concentrations of PCNs were found between samples of formula for each of the three age groups. The mean TEQ for PCNs in goat milk formula samples (0.0031 pg TEQ/g ww) was higher than the value for cow milk formula (0.0009 pg TEQ/g ww) produced in China, and the proportion of higher chlorinated PCNs in goat milk formula was also higher. Based on dry weight, the mean concentration of PCNs in the raw cow milk (119 pg/g dry weight (dw)) used to produce infant and toddler formula was higher than that in the actual formula (24.2 pg/g dw), and the PCN profiles also varied between the raw milk and formula. A risk assessment indicated that, in China, consuming formula poses a lower risk to infants and toddlers from based on exposure to PCNs compared with consuming breast milk.

A Review on Tetrabromobisphenol A: Human Biomonitoring, Toxicity, Detection and Treatment in the Environment

Tetrabromobisphenol A (TBBPA) is a known endocrine disruptor employed in a range of consumer products and has been predominantly found in different environments through industrial processes and in human samples. In this review, we aimed to summarize published scientific evidence on human biomonitoring, toxic effects and mode of action of TBBPA in humans. Interestingly, an overview of various pretreatment methods, emerging detection methods, and treatment methods was elucidated. Studies on exposure routes in humans, a combination of detection methods, adsorbent-based treatments and degradation of TBBPA are in the preliminary phase and have several limitations. Therefore, in-depth studies on these subjects should be considered to enhance the accurate body load of non-invasive matrix, external exposure levels, optimal design of combined detection techniques, and degrading technology of TBBPA. Overall, this review will improve the scientific comprehension of TBBPA in humans as well as the environment, and the breakthrough for treating waste products containing TBBPA.

Per- and polyfluoroalkyl substances (PFAS) in breast milk and infant formula: A global issue

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are transferred from mother to infants through breastfeeding, a time when children may be particularly vulnerable to PFAS-mediated adverse health effects. Infants can also be exposed to PFAS from infant formula consumption. Our recent literature-based scoping of breast milk levels reported that four PFAS often exceeded the United States Agency for Toxic Substances and Disease Registry (ATSDR) children's drinking water screening levels in both the general population and highly impacted communities in the U.S. and Canada. This work presents a comparison of global breast milk and infant formula PFAS measurements with the only reported health-based drinking water screening values specific to children.

METHODS

We focused on four PFAS for which ATSDR has developed children's drinking water screening values: PFOA (perfluorooctanoic acid), PFOS (perfluorooctanesulfonic acid), PFHxS (perfluorohexanesulfonic acid), and PFNA (perfluorononanoic acid). Published literature on PFAS levels in breast milk and infant formula were identified via PubMed searches. Data were compared to children's drinking water screening values.

DISCUSSION

Breast milk concentrations of PFOA and PFOS often exceed children's drinking water screening values, regardless of geographic location. The limited information on infant formula suggests its use does not necessarily result in lower PFAS exposures, especially for formulas reconstituted with drinking water containing PFAS. Unfortunately, individuals generally cannot know whether their infant's exposures exceed children's drinking water screening values. Thus, it is essential that pregnant and lactating women and others, especially those having lived in PFAS-contaminated communities, have data required to make informed decisions on infant nutrition. An international monitoring effort and access to affordable testing are needed for breast milk, drinking water and infant formula to fully understand infant PFAS exposures. Currently, our understanding of demonstrable methods for reducing exposures to emerging PFAS is limited, making this research and the communications surrounding it even more important.

First WHO/UNEP survey of the current concentrations of persistent organic pollutants in human milk in Morocco

The presence of persistent organic pollutants (POPs) in human milk is an indicator of the level of these substances in the environment and enables evaluation of the potential exposure of breastfed children. POPs concentrations in a Moroccan human milk pooled sample (59 donors) were determined for the first time by the WHO reference laboratory to provide a baseline and allow monitoring of the future trends for those persistent organohalogen compounds. Eighty-one different POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dioxins and furans (PCDD/Fs) were identified and quantified by using gas chromatography (GC) with an electron capture detector (ECD) and confirmed by gas chromatography-mass spectrometry (GC/LRMS). The obtained results showed that the sum of DDT (sum of o,p'-DDD, p,p'-DDD, o,p'-DDE, p,p'-DDE, o,p'-DDT, and p,p'-DDT) was 237.9 ng/g, representing 94.0% of all detected OCPs levels, with a dominance of p,p'-DDE, and p,p'-DDT. Cis-heptachlor epoxide, HCB, and HCH were found at much lower levels. PCB indicator level was 60.7 ng/g of lipid, with the dominance of PCB 138, PCB 153, and PCB 180, presenting 98.3% of the total. Among the 25 PBDE congeners quantified, BDE-47, BDE-153, BDE-197, and BDE-207 were the dominant congeners account for 15.4% of the total concentration of PBDE (1.3 pg/g lipid). The lipid-adjusted level of PCDD/Fs and dl-PCBs expressed in Toxic Equivalents (TEQs: 6.65 pg/g) were lower in comparison to those found in the other countries. In summary, detected POPs levels in Moroccan human milk were much lower compared to the other countries, reflecting the effectiveness of the compliance with Stockholm Convention requirements on eliminating or reducing emissions of selected POPs. Continued monitoring is needed for these compounds, for which this is the first data available, provided by the WHO/UNEP survey in Morocco.

Concentrations of Per- and Polyfluoroalkyl Substances in Paired Maternal Plasma and Human Milk in the New Hampshire Birth Cohort

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent endocrine-disrupting chemicals associated with long-term health outcomes. PFAS are transferred from maternal blood to human milk, an important exposure source for infants, and understanding of this transfer is evolving. We characterized concentrations of 10 PFAS in human milk (n = 426) and compared milk-to-plasma concentrations of 9 PFAS among a subset of women with paired samples (n = 294) from the New Hampshire Birth Cohort Study using liquid chromatography-isotope dilution tandem mass spectrometry. We examined the relationship between perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in plasma versus milk and fit linear regression models to assess relationships between milk PFOA and PFOS and participant characteristics. The median plasma PFOA concentration was 0.94 ng/mL (interquartile range, IQR, 0.59-1.34) and that of PFOS was 2.60 ng/mL (IQR 1.80-3.90); the median milk PFOA concentration was 0.017 ng/mL (IQR 0.012-0.027) and that of PFOS was 0.024 ng/mL (IQR 0.016-0.036). PFOA and PFOS plasma and milk concentrations showed correlations of ρ = 0.83 and 0.77, respectively (p < 0.001). Parity, previous lactation, week of milk collection, and body mass index were inversely associated with milk PFAS. We estimate that even among our general population cohort, some infants (∼6.5%) are exposed to amounts of PFAS via milk that may have long-term health impacts.

The toxicological profile of polychlorinated naphthalenes (PCNs)

The legacy of polychlorinated naphthalenes (PCNs) manufactured during the last century continues to persist in the environment, food and humans. Metrological advances have improved characterisation of these occurrences, enabling studies on the effects of exposure to focus on congener groups and individual PCNs. Liver and adipose tissue show the highest retention but significant levels of PCNs are also retained by the brain and nervous system. Molecular configuration appears to influence tissue disposition as well as retention, favouring the higher chlorinated (≥ four chlorines) PCNs while most lower chlorinated molecules readily undergo hydroxylation and excretion through the renal system. Exposure to PCNs reportedly provokes a wide spectrum of adverse effects that range from hepatotoxicity, neurotoxicity and immune response suppression along with endocrine disruption leading to reproductive disorders and embryotoxicity. A number of PCNs, particularly hexachloronaphthalene congeners, elicit AhR mediated responses that are similar to, and occur within similar potency ranges as most dioxin-like polychlorinated biphenyls (PCBs) and some chlorinated dibenzo-p-dioxins and furans (PCDD/Fs), suggesting a relationship based on molecular size and configuration between these contaminants. Most toxicological responses generally appear to be associated with higher chlorinated PCNs. The most profound effects such as serious and sometimes fatal liver disease, chloracne, and wasting syndrome resulted either from earlier episodes of occupational exposure in humans or from acute experimental dosing of animals at levels that reflected these exposures. However, since the restriction of manufacture and controls on inadvertent production (during combustion processes), the principal route of human and animal exposure is likely to be dietary intake. Therefore, further investigations should include the effects of chronic lower level intake of higher chlorinated PCN congeners that persist in the human diet and subsequently in human and animal tissues. PCNs in the diet should be evaluated cumulatively with other similarly occurring dioxin-like contaminants.

Polychlorinated dioxins and dibenzofurans (PCDD/F), polybrominated dioxins and dibenzofurans (PBDD/F), polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), and per- and polyfluoroalkyl substances (PFAS) in German breast milk samples (LUPE 8)

Most organic pollutants (POP) are persistent in the environment, accumulate in fatty tissues, and so a transfer through the food chain is probably, thereby causing various health effects. We quantified PCDD/F, PBDD/F, PCB, PBDE, perfluorinated substances, and ADONA in breast milk samples collected in two German federal states and breast milk and blood samples from subjects additionally exposed to PFOA. The median (95th percentile) concentrations were 2.43 (6.58) pgWHO₂₀₀₅TEQ/g l.w. for PCDD/F, 2.45 (4.82) pgWHO₂₀₀₅TEQ/g l.w. for dioxin-like PCB (dl-PCB), and 0.62 (2.69) pgWHO₂₀₀₅TEQ/g l.w. for PBDD/F. The relative contributions of the median values of PCDD/F, dl-PCB, and PBDD/F to the total-TEQ were approximately 41%, 42%, and 11%, respectively. Nondioxin-like PCB (ndl-PCB) concentrations were clearly dominated by the higher chlorinated PCB congeners, with medians of 23.2 ng/g l.w. for PCB 153, 13.9 ng/g l.w. for PCB 138, and 13.0 ng/g l.w. for PCB 180. The sum of the 3 congeners (PCB 138, 153, and 180) were multiplied with 1.64 (total PCB) and showed a median of 82.16 ng/g l.w. and a 95th percentile of 173.3 ng/g l.w. Only PFOA and PFOS could be quantified in 29% and 17% of in total 180 samples with 95th percentiles of 53 ng/l and 33 ng/l, respectively. Milk samples (n = 13) from subjects living on PFOA contaminated sites showed higher levels between 33 and 854 ng/l PFOA (mean: 199 ng/l), whilst PFOS could be quantified only in three samples. The sum of 17 PBDE congeners showed medians (95th percentile) of 1737 pg/g l.w. (22,806 pg/g l.w.), with the highest medians of 422 pg/g l.w. for BDE 209 and 378 pg/g l.w. for BDE 153. Overall, our study confirms the declining contamination level in breast milk during the last decade, but points out the need to further reduce the environmental contamination with persistent substances and subsequently the exposure in childhood.

Comprehensive Evaluation of Dietary Exposure and Health Risk of Polychlorinated Naphthalenes

Intake from food is considered an important route of human exposure to polychlorinated naphthalenes. To our knowledge, several studies have quantified dietary exposure but only in European countries and measuring only a few of the 75 congeners. In addition, the influence of source diversity on human exposure has seldom been assessed. We analyzed 192 composite food samples composed of 17,280 subsamples from 24 provinces in China to measure the concentrations of polychlorinated naphthalenes and estimate their daily intake and potential health risks on a national scale. The estimated cancer risk was in the range of 6.8 × 10^-8 to 4.6 × 10^-7. We compared our findings for 75 congeners with reports in the literature that quantified only 12 congeners. We estimate that these 12 congeners contribute only approximately 4% to the total mass daily intake of polychlorinated naphthalenes and 70% to the total toxic equivalent quantity, indicating underestimation of dietary exposure. The contributions of combustion-associated congeners to the total concentrations of polychlorinated naphthalenes were in the range of 31-52%, suggesting that the ongoing unintentional release of these compounds from industrial thermal processes is an important factor in polychlorinated naphthalene contamination and human exposure in China.

A review on environmental occurrence, toxic effects and transformation of man-made bromophenols

Brominated phenols (BPs) of anthropogenic origin are aromatic substances widely used in the industry as flame retardants (FRs) and pesticides as well as the components of FRs and polymers. In this review, we have focused on describing 2,4-dibromophenol (2,4-DBP), 2,4,6-tribromophenol (2,4,6-TBP) and pentabromophenol (PBP), which are the most commonly used in the industry and are the most often detected in the air, aquatic and terrestrial ecosystems and the human body. This review describes human-related sources of these BPs that influence their occurrence in the environment (atmosphere, surface water, sediment, soil, biota), indoor air and dust, food, drinking water and the human organism. Data from in vitro and in vivo studies showing 2,4-DBP, 2,4,6-TBP and PBP toxicity, including their estrogenic activity, effects on development and reproduction, perturbations of cellular redox balance and cytotoxic action have been described. Moreover, the processes of BPs transformation that occur in human and other mammals, plants and bacteria have been discussed. Finally, the effect of abiotic factors (e.g. UV irradiation and temperature) on BPs conversion to highly toxic brominated dioxins and brominated furans as well as polybrominated biphenyls and polybrominated diphenyl ethers has been presented.

Brominated and chlorinated contaminants in food (PCDD/Fs, PCBs, PBDD/Fs PBDEs): Simultaneous determination and occurrence in Italian produce

Validated methodology for the simultaneous determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs) in foods of animal origin is presented. Method performance indicators were equivalent or better than those required for the control of EU regulated (EU, 2017/644) PCDD/F and PCB congeners in these foods, and for risk assessment through dietary intake. The method uses a high (>90%) proportion of ¹³Carbon-labelled surrogates for internal standardisation combined with high resolution mass spectrometry that allow accurate quantitation, and this was confirmed by multiple successful participations in proficiency testing for PCDD/Fs, PCBs and PBDEs in food. The same validation and method performance requirements as used for PCDD/Fs were followed for PBDD/Fs. The analysis of a range of food samples (eggs, milk, fish, shellfish, pork, beef and poultry), showed the occurrence of all four classes of contaminants at varying concentration ranges. In general, PCBs were the most prominent contaminant, both, in terms of dioxin-like toxicity, as well as in the occurrence of non-dioxin-like congeners, an observation that concurs with those made in other studies on Italian foods. The levels of PCDD/F and PCB occurrence are consistent with a gradual decline in contamination as reported by some other similar studies. Although all the determined contaminants were detected in the sampled foods, there was poor correlation between the occurrences of the brominated and chlorinated contaminants, and between PBDEs and PBDD/Fs, but better associations were observed between the occurrences of the chlorinated contaminants.

Legacy brominated flame retardants in human milk from the general population in Beijing, China: Biomonitoring, temporal trends from 2011 to 2018, and nursing infant's exposure assessment

Three kinds of legacy brominated flame retardants (BFRs), including eight polybrominated diphenyl ether (PBDE) congeners, tetrabromobisphenol A (TBBPA), and three hexabromocyclododecane (HBCDD) isomers, were analyzed in 105 human milk samples collected in 2018 from Beijing, China. The tested BFRs all showed high detection frequencies, and HBCDD was the most abundant BFR, with a median level of 7.64 × 10³ pg/g lipid, followed by BDE-153 (389 pg/g lipid), BDE-209 (283 pg/g lipid), and TBBPA (271 pg/g lipid). By comparing the results of the present study with those of our previous Beijing human milk surveys conducted in 2014 and 2011, the contamination of TBBPA and HBCDD increased steadily from 2011 to 2018, whereas that of PBDEs decreased sharply during this period. Our results suggested that the production and consumption of BFRs in China have shifted from PBDEs to other FRs. Education level and the consumption of animal-derived foods such as eggs and meat were identified as major influencing factors for some BFRs. For nursing infants, the median levels of lower bound BFR daily intake via human milk ingestion ranged from 4.62 × 10^-2 ng/kg bw/day for BDE-154 to 30.6 ng/kg bw/day for HBCDD. The daily intake of most BFRs by breastfeeding is unlikely to pose significant health risks for Beijing nursing infants. However, the minimum margin of exposure (MOE) of HBCDD was below its threshold value, which indicated that its daily intake might raise health concerns for some breastfed infants.

Health toxicity effects of brominated flame retardants: From environmental to human exposure

Hexabromocyclododecane (HBCD) and Tetrabromobisphenol A (TBBP-A) are brominated flame retardants widely used in variety of industrial and consumer products (e.g., automobiles, electronics, furniture, textiles and plastics) to reduce flammability. HBCD and TBBPA can also contaminate the environment, mainly water, dust, air and soil, from which human exposure occurs. This constant exposure has raised some concerns against human health. These compounds can act as endocrine disruptors, a property that gives them the ability to interfere with hormonal function and quantity, when HBCD and TBBPA bind target tissues in the body. Studies in human and animals suggest a correlation between HBCD and TBBPA exposure and adverse health outcomes, namely thyroid disorders, neurobehavior and development disorders, reproductive health, immunological, oncological and cardiovascular diseases. However, in humans these effects are still poorly understood, once only a few data evaluated the human health effects. Thus, the purpose of this review is to present the toxicity effects of HBCD and TBBPA and how these compounds affect the environment and health, resorting to data and knowledge of 255 published papers from 1979 to 2020.

Multiple persistent organic pollutants in mothers' breastmilk: Implications for infant dietary exposure and maternal thyroid hormone homeostasis in Uganda, East Africa

Persistent organic pollutants (POPs) are ubiquitous contaminants with adverse health effects in the ecosystem. One of such effects is endocrine disruption in humans and wildlife even at background exposure concentrations. This study assessed maternal breastmilk concentrations of POPs; brominated flame retardants (BFRs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), and the potential health risks posed to the nursing infants. We also evaluated the association of these POPs with total 3,3',5-triiodo-L-thyronine (T₃), L-thyroxine (T₄), and 3,3',5'-triiodo-L-thyronine (rT₃) levels measured in human breast milk. Thirty breastmilk samples were collected from Kampala, Uganda between August and December 2018. Hexabromobenzene was not detected while the maximum level of 2,2',4,4',5,5'-hexabrombiphenyl was 64.7 pg/g lw. The median levels of total indicator PCBs, PBDEs, dioxin-like PCBs, and PCDD/Fs in the samples were 159 pg/g lw, 511 pg/g lw, 1.16 pg TEQ/g lw, and 0.4 pg TEQ/g lw, respectively. These levels were lower than those reported in other countries. Owing to their bio accumulative nature, PCBs -81, -169, and ∑PCDD/Fs increased with increase in maternal age. Estimated dietary intakes for dioxin-like PCBs and PCDD/Fs were lower than those reported elsewhere but were higher than the WHO tolerable daily intakes suggesting potential health risks to nursing infants. In adjusted single pollutant models, PCB-126, PCB-169, and ∑PCB_TEQ were negatively associated with T₃, while 1,2,3,4,5,7,8-HpCDF was positively associated with rT₃. Although these associations did not persist in multipollutant models, our findings suggest potential thyroid hormone disruption by POPs in mothers. This may reduce the levels of thyroid hormones transferred from the mother to the neonates and, hence, adversely influence infant growth. A temporal study with a bigger sample size is required to corroborate these findings.

Burden and Risk of Polychlorinated Naphthalenes in Chinese Human Milk and a Global Comparison of Human Exposure

Polychlorinated naphthalenes (PCNs) are carcinogenic contaminants. Residues from historical production and ongoing unintentional releases from industrial thermal sources have led to the ubiquitous presence of PCNs in the environment. Our previous study has revealed that unintentional releases may be the main sources of PCNs in human milk from China. However, an assessment of PCN burden in human milk and exposure differences between historical residues and unintentional release exposure has not been conducted. In this study, we performed the first comparison of human exposure to PCNs and evaluated the differences between the estimated health risks from historical residues and unintentional releases. Three characteristic PCN congener patterns found in Chinese human milk specimens collected from 100 cities/counties can be considered characteristic of PCN exposures in regions with unintentional industrial releases as the main PCN sources. The health risk assessment suggested potential noncarcinogenic health effects in infants aged 0-6 months. The hazard index calculated for infants in Sweden indicates a strong impact of historical residues that nonetheless decreases over time, and a comparison of the hazard indices calculated for China and Ireland suggests that ongoing unintentional formation and release of PCNs from industrial processes should be a matter of public health concern.

Polybrominated dibenzo-p-dioxins and furans (PBDD/Fs): Contamination in food, humans and dietary exposure

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) have been recognised as environmental pollutants for decades but their occurrence in food has only recently been reported. They elicit the same type of toxic response as analogous polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) with similar potencies and effects, and share similar origins - inadvertent production during combustion and occurrence as by-products in industrial chemicals. Surprisingly, PBDD/Fs have received considerably less attention than PCDD/Fs, perhaps because determination requires a higher degree of analytical competence, a result of the higher adsorptivity and lability associated with carbon-bromine bonding. For most populations, the principal exposure pathway is dietary intake. The PBDD/F toxicity arising from occurrence in foods has often been expressed as toxic equivalents (TEQs) using the same scheme developed for PCDD/Fs. This approach is convenient, but resulting TEQ estimates are more uncertain, given the known differences in response for some analogous congeners and also the different patterns of PBDD/F occurrence confirmed by the newer data. Further studies to consolidate potency factors would help to refine TEQ estimates. Characteristically, most foods and human tissues show more frequent and higher PBDF concentrations relative to PBDDs, reflecting major source patterns. Occurrence in food ranges from <0.01 to several thousand pg/g (or up to 0.3 pg TEQ/g whole weight) which is comparable to PCDD/F occurrence (ΣPBDD/F TEQs are underestimated as not all relevant congeners are included). Plant based foods show higher PBDD/F: PCDD/F TEQ ratios. Reported PBDD/F dietary intakes suggest that some population groups, particularly young children, may exceed the revised tolerable weekly intake for dioxin-like contaminants (2 pg TEQ/kg bw/week), even for mean consumption estimated with lower bound data. It is evident that the omission of PBDD/Fs from the TEQ scheme results in a significant underestimation of the cumulative toxicity and associated risk arising from this mode of action.

Update of the risk assessment of hexabromocyclododecanes (HBCDDs) in food

The European Commission asked EFSA to update its 2011 risk assessment on hexabromocyclododecanes (HBCDDs) in food. HBCDDs, predominantly mixtures of the stereoisomers α-, β- and γ-HBCDD, were widely used additive flame retardants. Concern has been raised because of the occurrence of HBCDDs in the environment, food and in humans. Main targets for toxicity are neurodevelopment, the liver, thyroid hormone homeostasis and the reproductive and immune systems. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour in mice can be considered the critical effects. Based on effects on spontaneous behaviour in mice, the Panel identified a lowest observed adverse effect level (LOAEL) of 0.9 mg/kg body weight (bw) as the Reference Point, corresponding to a body burden of 0.75 mg/kg bw. The chronic intake that would lead to the same body burden in humans was calculated to be 2.35 μg/kg bw per day. The derivation of a health-based guidance value (HBGV) was not considered appropriate. Instead, the margin of exposure (MOE) approach was applied to assess possible health concerns. Over 6,000 analytical results for HBCDDs in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary LB exposure to HBCDDs were fish meat, eggs, livestock meat and poultry. The CONTAM Panel concluded that the resulting MOE values support the conclusion that current dietary exposure to HBCDDs across European countries does not raise a health concern. An exception is breastfed infants with high milk consumption, for which the lowest MOE values may raise a health concern.

Exposure and health risk assessment of secondary contaminants closely related to brominated flame retardants (BFRs): Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in human milk in shanghai

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), as the secondary environmental pollutants of the widely used brominated flame retardants (BFRs), possess the similar physicochemical and toxic properties as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). However, studies on human body exposure to them are extremely limited. In this study, forty human milk samples collected in Shanghai were measured for 13 PBDD/F congeners using gas chromatography-high resolution mass spectrometry (GC-HRMS), to investigate their exposure level and characteristics, potential source and corresponding health risks to breastfed infants. The results showed no PBDDs but three PBDF congeners including 2,3,7,8-TBDF, 1,2,3,4,6,7,8-HpBDF and OBDF (mean concentration (detection rates) are 3.2 pg/g (72.5%), 9.5 pg/g (100%) and 28 pg/g (67.5%), respectively) were detected. The average toxic equivalent quantity (TEQ, 0.42 pg/g lw) presented the highest concentration level compared to other regions reported. The contribution of PBDFs to the total TEQ of PBDD/Fs and PCDD/Fs is 6.8%. The correlation between PBDD/Fs and age or dietary habits was not observed, which normally existed in their chlorinated analogues-PCDD/Fs. Significant correlations were observed between PBDFs and highly brominated polybrominated diphenyl ethers (PBDEs) (especially for BDE 183 and BDE 209). The correlation between PCDD/Fs and PBDFs was not observed except 2,3,7,8-TBDF. The high PBDFs exposure in Shanghai may originate from the emission of PBDEs and/or non-PBDE BFRs in environment, according to the consistency of the environmental data previously reported. The average estimated dietary intakes (EDI) for breastfed infants is 2.0 pg TEQ/kg·bw/day (0.13-13 pg TEQ/kg·bw/day), within the range of the tolerable daily intake (TDI) for TCDD (1-4 pg TEQ/kg·bw/day) suggested by the World Health Organization (WHO). However, given the high toxicity of PBDD/Fs, the potential health risks of these pollutants for breastfed infants should be of concern.

Infant dietary exposure to dioxin-like polychlorinated biphenyls (dlPCBs), polybrominated and mixed halogenated dibenzo-p-dioxins and furans (PBDD/Fs and PXDD/Fs) in milk samples of lactating mothers in Accra, Ghana

In this study, polybrominated and mixed halogenated dibenzo-p-dioxins and furans (PBDD/Fs and PXDD/Fs), and dioxin-like polychlorinated biphenyls (dlPCBs) were quantified in 24 human milk samples of first-time lactating mothers from Greater Accra region in Ghana. The aims of the study were to determine the concentrations and toxic equivalent concentrations of PBDD/F, PXDD/F and dlPCBs in human milk, and to estimate an infant's daily intake. The samples were analysed for 12 dioxin-like PCBs, 7 congeners of 2,3,7,8-polybrominated dibenzo-p-dioxins and furans (PBDD/Fs), and 7 congeners of 2,3,7,8-mixed halogenated dioxins and furans (PXDD/Fs, where X = Br/Cl). The mean concentrations in human milk ranged from 0.15 to 212.9 pg/g lipid for dlPCB congeners (mean TEQ: 1.67 pg WHO₂₀₀₅-TEQ/g lipid). Lesser concentrations for 2,3,7,8-PXDD/Fs (and PBDD/Fs congeners) ranged between <0.01-1.67 pg/g lipid, with a total mean tentative TEQ of 0.56 pg WHO₂₀₀₅-TEQ/g lipid. For an infant of average weight 7 kg, consuming an estimated volume of 600 mL human milk, the estimated average daily intake of dlPCBs in 21 human milk samples was 4.95 pg TEQ/kg bw/day; contributions from dlPCBs, PXDD/Fs and PBDD/Fs resulted in an average estimated daily intake of 6.56 pg TEQ/kg bw/day. The results obtained in this study, although lower than infant dietary intake estimates in human milk from industrialized countries, exceeded the recommended safety standards of 1 pg TEQ/kg bw/day and 1-4 pg TEQ/kg bw/day from the Agency for Toxic Substances and Disease Registry (ATSDR) and the World Health Organization (WHO), respectively.

Polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) in Italian food: Occurrence and dietary exposure

Human exposure to polychlorinated dioxins and furans (PCDD/Fs) through the dietary pathway is widely recognised and regulations in some regions of the world help to limit food contamination. Similar information on the analogous polybrominated dioxins and furans (PBDD/Fs) is scarce, partly due to the higher threshold to analytical access and unavailability of some standard materials. The analytical methodology developed here determined twelve planar PBDD/F congeners using ¹³Carbon labelled PBDD/F surrogates and high resolution mass spectrometric detection, and was extensively validated prior to the analysis of a range of commonly consumed Italian foods. The methodology also allowed simultaneous determination of PCDD/Fs and polychlorinated biphenyls (PCBs). The results show that PBDD/Fs occurred in different foods over a range of concentrations from <0.001 pg/g to 4.58 pg/g in fish. The dietary exposure (upper bound) of different Italian population groups, resulting from these occurrence levels was estimated using the toxic equivalency (TEQ) approach that is commonly used for dioxin-like contaminants and ranged from 0.17 to 0.42 pg TEQ/kg bodyweight/day (lower bound - 0.01 pg TEQ/kg bodyweight/day) depending on the population subgroup. Although precautionary, upper bound values may provide a more realistic estimate of toxicity as not all congeners and foods were measured. As expected, children were more highly exposed than adults due to lower body weight. These exposure levels were between a quarter and a third of that arising from the sum of PCDD/Fs and PCBs (0.61 to 1.38 pg WHO-TEQ/kg bodyweight/day), but they contribute to dioxin-like toxicity. If this data is considered in view of the revised tolerable dioxin-like dietary intake published by EFSA in 2018, it is evident that the tolerable weekly intake of 2 pg/kg bodyweight/week would be exceeded by some of the assessed population sub-groups, or all sub-groups if the cumulative intake is considered.

Dietary exposure assessment of a nursing mother-infant cohort to legacy and novel brominated flame retardants: Results of a 3-day duplicate diet study in Beijing, China

In a 3-day duplicate diet study of a nursing mother-infant cohort (n = 20), the levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), and 5 novel brominated flame retardants (BFRs) were measured in 60 24-h duplicate diet samples and 20 breast milk samples provided by the mothers. The dietary BFR intake and related health risks of the mothers and their babies due to food consumption or human milk ingestion were subsequently assessed. At median concentrations of 284, 264 and 177 pg/g wet weight (ww) in the diet, decabrominated diphenyl ethers (BDE-209), decabromodiphenyl ethane (DBDPE) and HBCDD were predominant among the total BFRs. In human milk, HBCDD was the most abundant BFR, followed by BDE-209 and DBDPE, which indicates that BDE-209 and HBCDD have remained ubiquitous in the environment because of their continuous production and use in China. Meanwhile, concentrations of DBDPE were comparative to those of PBDEs and HBCDD in both diet and human milk, and DBDPE also had much higher concentrations than any other NBFRs, which indicates that the BFR consumption pattern in China is shifting from legacy BFRs to NBFRs. The median estimated dietary intakes (EDIs) of BDE-209, HBCDD and DBDPE for the mothers were 6.83, 3.73 and 5.44 ng/kg bw/day, respectively, and EDIs for their nursing babies were 24.7, 41.9 and 7.83 ng/kg bw/day, respectively. The nursing infants showed higher BFR body burden than the mothers. However, the EDIs obtained for both mothers and their babies discloses a low health risk to this mother-infant cohort.

Polybrominated dibenzo-p-dioxins (PBDDs) and - dibenzofurans (PBDFs) in cod (Gadus morhua) liver-derived products from 1972 to 2017

Literature data on the occurrence and prevalence of polybrominated dibenzo-p-dioxins (PBDDs) and polybrominated dibenzofurans (PBDFs) in foods including seafood are scarce. In this study, a number of cod-derived products including medicinal grade cod liver oils sourced from Northern Atlantic waters (Iceland, Norway) and the Baltic Sea (Poland) during 1972-2001 and canned cod liver sourced from the Baltic Sea in 2017, showed detectable levels of PBDFs: such as 2,3,8-TrBDF at 0.57 to 5.249 pg g^-1 fat and 1,2,3,4,6,7,8-HpBDF at <0.018 to 0.302 pg g^-1 fat. PBDDs were not detected in the cod liver oils. Canned cod liver products showed low levels of 2,3,7,8-TeBDD in the range <0.017 to 0.022 pg g^-1 whole weight and 1,2,3,7,8-PeBDD at <0.03 to 0.039 pg g^-1 whole weight. These concentrations were computed to yield upper bound toxic equivalences (TEQs) of 0.14 to 0.17 pg g^-1 for the oils and 0.12 to 0.25 pg g^-1 for the canned products (0.08 pg g^-1 ww for both products). The resulting supplementary and dietary intakes are low (0.02 to 0.11 pg kg^-1 bm day^-1 for the oils and 0.07 to 0.17 pg kg^-1 bm week^-1 for the canned livers) in comparison to the recently expressed tolerable weekly intake of 2 pg kg^-1 bm week^-1. However, the intakes are underestimates, as due to a lack of analytical standards not all PBDD/F TEQ contributing congeners could be included. The PBDD/F TEQ contributes to the cumulative toxicity arising from other contaminants such as chlorinated dioxins and polychlorinated biphenyls.

Dioxin-like polybrominated biphenyls (PBBs) and ortho-substituted PBBs in edible cod (Gadus morhua) liver oils and canned cod livers

This study investigates the occurrence of polybrominated biphenyls (PBBs), a legacy flame retardant, in fishery products such as medicinal grade cod liver oils and canned liver products, sourced from the North Atlantic during 1972-2017. It also assesses the dietary and supplementary (the oils were commonly administered as dietary supplements to children and youth) intake of PBBs from these products. Summed ortho-PBB concentrations ranged from 770 to 1400 pg g^-1 fat in the oils and from 99 to 240 pg g^-1 whole weight in canned livers, with PBB-49, 52, 101 and 153 accounting for most of these levels. Among the more toxic non-ortho-PBBs, PBB-126 and PBB-169 were not detected, but PBB-77 concentrations ranged from 0.6 to 5.78 pg g^-1 fat in the oils and 0.06-0.126 pg g^-1 whole weight in canned livers. During 1972-1993, PBB contamination levels were similar for cod liver oils from the Baltic Sea and other North Atlantic regions, but over the timescale of the study, Baltic Sea products appear to show a decline in PBB concentrations. As PBB-77 was the only dioxin-like PBB detected in the samples, the corresponding supplementary (oils, 1972-2001) and dietary (cod liver from 2017) intakes were very low, at < 0.001 pg TEQ kg^-1 bm d^-1 (or < 0.01 pg TEQ kg^-1 bm d^-1 upper bound) for the sum of all the measured dioxin-like PBBs -four to six orders of magnitude lower than that arising from other dioxin-like contaminants that were shown to occur in these products, from earlier studies.

Concentrations of perfluoroalkyl substances in human milk from Ireland: Implications for adult and nursing infant exposure

Concentrations of 10 perfluoroalkyl substances (PFASs) were measured in 16 pools of human milk from Ireland. Only four PFASs were detected (PFOA, PFNA, PFHxS and PFOS), with concentrations dominated by PFOA which was detected in all samples at a median of 0.10 ng/mL. Concentrations and the relative abundance of PFASs in human milk from Ireland are within the range reported for other countries. Estimated exposures for nursing infants to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) do not suggest a health concern. A one compartment pharmacokinetic model was used to predict the intakes of PFOS and PFOA required to support the observed concentrations in human milk. This suggests current adult exposure in Ireland to PFOS is below the provisional tolerable weekly intake (TWI) proposed by EFSA. In contrast, the model predicts that the maximum concentration detected in human milk in this study, implies a level of adult exposure that would exceed EFSA's provisional TWI for PFOA. As exposure of the Irish population to PFASs via drinking water, indoor air and dust is well-characterised, current understanding suggests that the major contributor to overall exposure of the Irish population is via the diet and/or less well-studied pathways like dermal uptake from PFAS-containing fabrics and cosmetics.

Tetrabromobisphenol A and hexabromocyclododecane isomers in breast milk from the general population in Beijing, China: Contamination levels, temporal trends, nursing infant's daily intake, and risk assessment

Two currently used brominated flame retardants (BFRs), α, β, γ-hexabromocyclododecane (HBCDD) and tetrabromobisphenol A (TBBPA), were measured in 111 breast milk samples from 37 Beijing mothers. Each mother provided one milk sample per month for 3 months. HBCDD was detected in almost all samples, and the median level reached 5.67 ng g^-1 lipid weight (lw). α- HBCDD was the most abundant isomer (median: 4.23 ng g^-1 lw), followed by γ- and β-HBCDD. For TBBPA, a relatively lower detecting frequency (64%) and contamination level (median: 1.57 ng g^-1 lw) were obtained. A comparison to our previous study revealed that the occurrence of TBBPA and HBCDD in Beijing human milk significantly rose from 2011 to 2014, whereas another commonly used class of BFRs, polybrominated diphenyl ethers (PBDEs), showed significantly decreased during this period. However, a comparison among currently used BFRs showed that levels of some BFRs, such as HBCDD, surpassed those of PBDEs, which indicated that PBDEs were no longer the primarily used BFR in China. However, no significant temporal trends for BFR levels were observed over the 3 months of lactation. Daily intakes of TBBPA and HBCDD were calculated for nursing infants and the median TBBPA and HBCDD intakes via breastfeeding were 6.62 and 26.4 ng kg^-1 bw day^-1, respectively. These values were several times higher than those for adults via food consumption. However, risk assessment using the margin of exposure approach indicated that intakes of TBBPA and HBCDD via breastfeeding can scarcely cause significant health risks to infants.

Polychlorinated naphthalenes in human milk: Health risk assessment to nursing infants and source analysis

Polychlorinated naphthalenes are teratogenic environmental contaminants. Mother milk is the most important food for nursing infants. The World Health Organization actively promotes breastfeeding for its immunological, psychological, and economic advantages. We firstly measured concentrations of polychlorinated naphthalenes in human milk from 19 provinces in China and estimated their potential health risks to nursing infants and their possible sources. Concentrations ranged from 211.07 to 2497.43 pg/g lipid. The high prevalence of highly toxic hexachlorinated naphthalenes (Hexa-CN66/67) in human milk samples indicated a higher health risk in the sampling areas. Cancer risk posed to nursing infants was not significant, but potential non-carcinogenic adverse health effects were suggested and should be emphasized in some sampling areas. Unintentional emission of polychlorinated naphthalenes from industries that employ thermal processes appears to be the main source for PCNs in human milk in most sampling areas. Correlation analysis also suggested PCNs as impurities in polychlorinated biphenyl mixtures as a previously unrecognized source of polychlorinated naphthalenes in human milk.

Persistent Organic Pollutants in Human Breast Milk and Associations with Maternal Thyroid Hormone Homeostasis

Epidemiological studies have indicated the thyroid-disrupting effects of persistent organic pollutants (POPs). However, the association of low-exposure POPs with thyroid hormones (THs) remains unclear. Here, we aim to assess the association of low exposure of POPs, including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and polybrominated dibenzo-p-dioxins and furans, with THs [total _L-thyroxine (TT₄), total 3,3',5-triiodo-_L-thyronine (TT₃), and total 3,3',5'-triiodo-_L-thyronine (TrT₃)] measured in human breast milk. Ninety-nine breast milk samples were collected from the LUPE cohort (2015-2016, Bavaria, Germany). Fourteen PBDEs, 17 PCBs, and 5 PCDD/Fs had quantification rates of >80%. Nonmonotonic associations were observed. In adjusted single-pollutant models, (1) TT₄ was inversely associated with BDE-99, -154, and -196; (2) TT₃ was inversely associated with BDE-47, -99, -100, -197, -203, -207, and OCDD; and (3) TrT₃ was inversely associated with BDE-47, -99, -183, and -203. Multipollutant analysis using principal component analysis and hierarchical clustering revealed inverse associations of PBDEs (BDE-28, -47, -99, -100, -154, -183, and -197) with TT₄ and TrT₃. These results indicate that POPs at low levels might be related to reduced THs. This study shows that human breast milk might be an appropriate specimen to evaluate the thyroid disruption of POPs.

Emerging and legacy brominated flame retardants in the breast milk of first time Irish mothers suggest positive response to restrictions on use of HBCDD and Penta- and Octa-BDE formulations

The brominated flame retardants (BFRs) hexabromocyclododecane (HBCDD), eight polybrominated diphenyl ethers (PBDEs), and decabromodiphenyl ethane (DBDPE) were measured in 16 pools of human milk from Ireland. Concentrations of BDEs-47, -99, -100, -153, and HBCDD were significantly lower (p < 0.05) than those in Irish human milk collected in 2011. In contrast, concentrations of BDE-209 in our study exceeded those in 2011, and while decabromodiphenyl ethane (DBDPE) was not detected in 2011 it was detected in 3 of our samples. This suggests increased use of DBDPE and that while restrictions on the Penta- and Octa-BDE formulations are reducing human exposure, those on Deca-BDE use have yet to reduce body burdens. Estimated exposures for nursing infants to all target BFRs do not suggest a health concern. A one compartment pharmacokinetic model was used to predict body burdens arising from BFR intakes via air, dust and diet. While for most targeted BFRs, predicted and observed body burdens derived from our human milk data compared reasonably well; predicted BDE-209 and DBDPE values were substantially lower than observed. This suggests exposure pathways not included in the model like dermal uptake from fabrics may be important, and highlights knowledge gaps about the human half-lives and bioavailability of these contaminants.

Perfluoroalkyl Substances in Drinking Water, Indoor Air and Dust from Ireland: Implications for Human Exposure

Perfluoroalkyl substances (PFASs) were measured in air and dust from cars, homes, offices, and school classrooms in Ireland, along with drinking water from homes and offices. Perfluorooctanoic acid (PFOA) dominated air and drinking water, while perfluorobutane sulfonate (PFBS) dominated dust. This is the first report of PFOA, perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), PFBS, and perfluorononanoic acid (PFNA) in air inside cars and school classrooms. PFOS concentrations in classroom air exceeded significantly (p ≤ 0.05) those in homes. Atmospheric concentrations of PFOA, PFNA, and methyl perfluorooctane sulfonamido ethanol (MeFOSE) (p ≤ 0.05) were significantly higher in cars containing child car seats than in cars without. PFOS, PFOA, PFBS, and PFHxS were all detected frequently in drinking water, but concentrations of PFASs were low, and although ΣPFASs were 64 ng/L in one bottled water sample, this fell below a Swedish Action Level of 90 ng ΣPFASs/L. The Irish population's exposure to PFOS and PFOA via non-dietary sources is well below estimates of dietary exposure elsewhere in Europe. Moreover, even under a high-end exposure scenario, it falls below the European Food Safety Authority's (EFSA) provisional tolerable weekly intakes for PFOS and PFOA.

Polybrominated diphenyl ethers and novel brominated flame retardants in human milk from the general population in Beijing, China: Occurrence, temporal trends, nursing infants' exposure and risk assessment

The levels of eight polybrominated diphenyl ether (PBDE) congeners, and six novel brominated flame retardants (NBFRs) were determined in human milk collected from Beijing, China in 2014. The tested 111 samples were collected from 37 mothers, and each donor provided one milk sample per month for 3 months after childbirth. Levels of ∑PBDEs (total tri- to deca-BDEs) were in the range of 0.288 to 22.2 ng g^-1 lw (lipid weight). BDE-209, with a median level of 2.2 ng g^-1 lw, was the predominant congener. Decabromodiphenyl ethane (DBDPE), as an NBFR and a substitute for deca-BDE, was found to be the most abundant BFR in all tested human milk (median:5.96 ng g^-1 lw). This result might suggest that the predominantly consumed BFRs in China have changed from PBDEs to PBDE substitutes. Additionally, a comparison to our previous studies conducted in 2005 and 2011 revealed that levels of tri- to hepta-BDEs showed significant reduction from 2005 to 2014, whereas levels of BDE-209 showed no significant variation from 2011 to 2014. Temporal trends of BFR levels over the three months of lactation were also investigated, and no significant changes were found in concentration with time over the three months lactation. For nursing infants up to 6 months old, the median lower bound of daily BFR intakes via human milk ingestion ranged from zero for 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) and 1,2-bis(2,4,6-tribromophenoxy)-ethane (BTBPE) to 18.7 ng kg^-1 bodyweight day^-1 for DBDPE. Although the daily dietary BFR intake for nursing infants was found to be much higher than that for adults, the risk assessment evaluated by the margin of exposure (MOE) approach revealed that dietary BFR intake for nursing infants was unlikely to pose significant health risks.

Tetrabromobisphenol A: Disposition, kinetics and toxicity in animals and humans

Tetrabromobisphenol A (TBBPA) is a nonregulated brominated flame retardant with a high production volume, and it is applied in a wide variety of consumer products. TBBPA is ubiquitous in abiotic matrices, wildlife and humans around the world. This paper critically reviews the published scientific data concerning the disposition, metabolism or kinetics and toxicity of TBBPA in animals and humans. TBBPA is rapidly absorbed and widely distributed among tissues, and is excreted primarily in the feces. In rats, TBBPA and its metabolites have limited systemic bioavailability. TBBPA has been detected in human milk in the general population. It is available to both the developing fetus and the nursing pups following maternal exposure. It has been suggested that TBBPA causes acute toxicity, endocrine disruptor activity, immunotoxicity, neurotoxicity, nephrotoxicity, and hepatotoxicity in animals. Cell-based assays have shown that TBBPA can induce reactive oxygen species in a concentration-dependent manner, and it promotes the production of inflammatory factors such as TNF α, IL-6, and IL-8. Cells exposed to high levels of TBBPA exhibit seriously injured mitochondria and a dilated smooth endoplasmic reticulum. This review will enhance the understanding of the potential risks of TBBPA exposure to ecological and human health.

Serum measures of hexabromocyclododecane (HBCDD) and polybrominated diphenyl ethers (PBDEs) in reproductive-aged women in the United Kingdom

We investigated the serum concentrations of two brominated flame retardants (BFRs) - polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD) -in 59 women aged between 23 and 42 from the United Kingdom. We also collected demographic data, including age, bodyweight and height in order to test for associations with BFR levels. Temporal and global differences were also assessed using previously published data. HBCDD was detected in 68% of samples with a mean concentration of 2.2 ng/g lipid (range = <0.3-13 ng/g lipid). The dominant stereoisomer was α-HBCDD with an average contribution of 82% (0-100%) towards ΣHBCDD, was followed by γ-HBCDD (average contribution = 17%). PBDEs were detected in 95% of samples with a mean ∑PBDE (sum of BDEs -28, -47, -99, -100, -153, -154 and -183) concentration of 2.4 ng/g lipid (range = <0.4-15 ng/g lipid). BDEs -153 and -47 were the dominant congeners, contributing an average of 40% and 37% respectively, to the average ΣPBDE congener profile. Data from this study suggests that HBCDD levels decrease with age, it also suggests a positive association between bodyweight and HBCDD levels, which likewise requires a large-scale study to confirm this. The data also show that 10 years after their European ban, PBDE body burden has begun to decrease in the UK. Whilst it is too early to draw any firm conclusions for HBCDDs, they appear to be following a similar pattern to PBDEs, with levels decreasing by a factor of >2.5 since 2010. Whilst the human body burden appear to be decreasing, both PBDEs and HBCDD are still consistently detected in human serum, despite legislative action limiting their production and use. This highlights the need to continuously assess human exposure and the effectiveness of policy aimed at reducing exposure.

Concentrations of Brominated Flame Retardants in Indoor Air and Dust from Ireland Reveal Elevated Exposure to Decabromodiphenyl Ethane

Concentrations of decabromodiphenyl ethane (DBDPE), 13 polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecane (HBCDD) were measured in indoor air and dust collected from Irish homes, cars, offices, and primary schools during 2016-2017. Median concentrations of DBDPE in air (88 pg/m³) and dust (6500 ng/g) significantly exceed those previously reported internationally, with concentrations highest in offices and schools, suggesting that DBDPE is widely used in Ireland. Median concentrations of BDE-209 in air (340 pg/m³) and dust (7100 ng/g) exceed or are within the range of concentrations reported recently for the same microenvironments in the U.K., and exceed those reported in many other countries. Concentrations of BDE-209 in cars exceeded significantly (p < 0.05) those in other microenvironments. HBCDD was detected in all dust samples (median: 580 ng/g), and in 81% of air samples (median: 24 pg/m³) at concentrations similar to those reported recently for the U.K. and elsewhere. Estimates of exposure to DBDPE of Irish adults (92 ng/day) and toddlers (210 ng/day) as well as to BDE-209 (220 ng/day and 650 ng/day for adults and toddlers, respectively) substantially exceed those reported for the U.K. population. Moreover, our estimates of exposure of the Irish population to Σtrideca-PBDEs exceed previous estimates for Ireland via dietary exposure.

Emissions, environmental levels, sources, formation pathways, and analysis of polybrominated dibenzo-p-dioxins and dibenzofurans: a review

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) were labeled potential persistent organic pollutants by the Stockholm Convention and have structures and toxicities similar to those of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), which has caused considerable concern. This article reviews the current available literature on the status, sources, formation pathways, and analysis of PBDD/Fs. PBDD/Fs are widely generated in industrial thermal processes, such as those for brominated flame retardant (BFR) products, e-waste dismantling, metal smelting processes, and waste incineration. PBDD/Fs can form via the following routes: precursor formation, de novo formation, biosynthesis, and natural formation. The levels of PBDD/Fs in the environment and in organisms and humans have increased due to extensive consumption and the increasing inventory of BFRs; thus, the risk of human exposure to PBDD/Fs is expected to be high.

Legacy and emerging brominated flame retardants in China: A review on food and human milk contamination, human dietary exposure and risk assessment

Brominated flame retardants (BFRs) are a large group of widely used chemicals, which have been produced and used since 1970s. As a consequence of substantial and long-term usage, BFRs have been found to be ubiquitous in humans, wildlife, and abiotic matrices around the world. Although several reports have reviewed BFRs contamination in general, none have focused specifically on foods and human milk, and the corresponding dietary exposure. Foods (including human milk) have long been recognized as a major pathway of BFRs intake for non-occupationally exposed persons. This review summarizes most available BFRs data in foods and human milk from China in recent years, and emphasizes several specific aspects, i.e., contamination levels of legacy and emerging BFRs, dietary exposure assessment and related health concerns, comparison between various BFRs, and temporal changes in BFRs contamination.

Levels of PCDD/Fs, PBDEs, and PBDD/Fs in Breast Milk from Southern Taiwan

This study investigates the congener-specific concentrations of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) in 25 breast milk samples from southern Taiwan. Most investigated congeners in Taiwanese breast milk are detectable except for PBDD/Fs. The geometric means of PCDD/Fs and PBDEs in the breast milk are 2.44 pg WHO₂₀₀₅-TEQ/g lipid and 2810 pg/g lipid. Several PCDD/F and PBDE congeners were highly correlated to each other like 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF (r = 0.919, p < 0.001). The longest duration of menstruation could be predicted by BDE-153 (β = 0.252) and 1,2,3,4,6,7,8-HpCDF (β = 0.345) with adjustment of confounders using a multiple stepwise linear regression model (r = 0.963, p < 0.001).

A national survey of tetrabromobisphenol-A, hexabromocyclododecane and decabrominated diphenyl ether in human milk from China: Occurrence and exposure assessment

A national survey of three currently used brominated flame retardants (BFRs), tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD) and decabrominated diphenyl ether (BDE-209) in human milk was conducted in 2011. Human milk from 16 provinces of China were collected, pooled and measured. The estimated daily intake (EDI) via human milk ingestion for nursing infant and the related health risks were evaluated. The median levels of TBBPA, HBCD and BDE-209 were 1.21, 6.83 and 0.556ng/g lipid weight (lw), respectively. Levels of BDE-209 were lower than those of TBBPA, indicating that the production and application of deca-BDE in China has been below that of TBBPA after the restriction of PBDEs. Moreover, contamination levels of TBBPA and HBCD in this survey were higher than those observed in last national survey conducted in 2007, indicating an increase of TBBPA and HBCD in the environment from 2007 to 2011. The mean estimated daily intakes (EDIs) of TBBPA, HBCD and BDE-209 via human milk for 1-6months old infant were 39.2, 51.7 and 3.65ng/kgbw/day, respectively. For risk assessment, margin of exposure (MOE) was calculated by comparing the BMDL₁₀ (benchmark dose lower confidence limit for a benchmark response of 10%) to the EDI of each BFR. Large MOEs indicates that the estimated dietary exposure to these three BFRs for nursing infant is unlikely to raise significant health concerns. Compared with some currently used novel BFRs which also measured in this survey, higher contamination levels were found in some non-PBDE BFRs, indicating that the consumption pattern of BFRs has shifted from PBDEs to non-PBDE BFRs in China.

Polybrominated diphenyl ethers and indicator polychlorinated biphenyls in human milk from China under the Stockholm Convention

Seven congeners of polybrominated diphenyl ethers (PBDEs) (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153,BDE-154 and BDE-183) and six indicator polychlorinated biphenyls (PCBs) (PCB-28, PCB-52, PCB-101, PCB-138, PCB-153 and PCB-180) were measured in 32 regional pooled human milk samples originating from 1760 volunteering primiparous mothers to evaluate the current human body burden of general population and the temporal trend in China. Individual human milk samples were collected following a WHO-designed procedure. This work is one of parts of the evaluation of effectiveness of Stockholm Convention performance. The concentration of ∑₇PBDEs ranged from 0.3 ng g^-1 lipid to 4.0 ng g^-1 lipid with a mean of 1.5 ng g^-1 lipid. The concentration of ∑₆PCBs ranged from 2.3 ng g^-1 lipid to 19.0 ng g^-1 lipid with a mean of 6.6 ng g^-1 lipid. By comparing with background determination in 2007, there was no significance for ∑₇PBDEs. However, BDE-47, BDE-99, and BDE-100 significantly decreased with an average of 45%, 48%, and 46%, respectively, from 2007 to 2011, and an increase of BDE-183 was founded in most regions. For ∑₆PCBs, there was a significant decline with an average reduction of 41% from 2007 to 2011. These results indicate the effectiveness of reduction and elimination of POPs in China. Future national human milk biomonitoring is worthy to be done to further evaluate the time trend and effectiveness of the Convention performance.

Distribution of polybrominated diphenyl ethers in breast milk, cord blood and placentas: a systematic review

Polybrominated diphenyl ethers (PBDEs) have been extensively used as flame retardants in consumer products. PBDEs rapidly bioaccumulate in the environment, food, wild animals and humans. In this review, we investigated the harmful effects of PBDEs on humans, especially in early life, and summarised the levels of PBDEs in human biological samples (breast milk, cord blood and placentas). In addition, we described the spatiotemporal distribution of PBDEs in this review. PBDE levels in breast milk, cord blood and placentas were generally higher in North America than in other regions, such as Asia, Europe, Oceania and Africa. However, high levels of PBDEs in human biological samples were detected at e-waste recycling sites in South China, East China and South Korea. This finding suggests that newborns living in e-waste regions are exposed to high levels of PBDEs during prenatal and postnatal periods. The time trends of PBDE concentration differed according to the region. Few studies have investigated PBDE levels in humans from 1967 to 2000, but they increased rapidly after 2000. PBDE concentration peaked at approximately 2006 globally. Compared with other PBDE congeners, BDE-47, BDE-153 and BDE-209 were the major components, but the detection rate of BDE-209 was lower than those of others. Future studies should focus on determining the BDE-209 concentration, which requires the implementation of different analytical approaches. Additionally, the levels of PBDEs in human samples and the environment should be monitored, especially in e-waste recycling regions. Graphical abstract The figures described the spatial distribution of the lowest (Fig. a1) and highest concentration of ∑PBDE (Fig. a2) in different countries by 2006 and described the spatial distribution of the lowest (Fig. b1) and highest concentration of ∑PBDE (Fig. b2) in different countries from 2007 to 2015. All the figures indicated that the levels of PBDEs in North America were substantially higher than those in many regions of Europe, Asia, Oceania, or Africa. Comparing Fig. a1-b1 or Fig. a2-b2, increasing trends were observed in some countries, especially in some regions in China, Korea and Canada.

Polychlorinated naphthalenes (PCNs) in food and humans

Polychlorinated naphthalenes (PCNs) are legacy contaminants that are listed by the Stockholm convention, initially for reduction of inadvertent production and ultimately, for elimination. They originate through releases from older electrical equipment, inadvertent contamination in industrial chemicals and from combustion processes such as incineration. Recent advances in measurement techniques have allowed a greater characterisation of PCN occurrence, yielding more specific data including individual PCN congener concentrations. Emerging data on food shows widespread occurrence in most commonly consumed foods from different parts of the world. Concurrently, toxicological studies have also allowed a greater insight into the potencies of some congeners, a number of which are known to elicit potent, aryl hydrocarbon receptor (AhR) mediated responses, often referred to as dioxin-like toxicity. The dietary pathway is widely recognised as the most likely route to non-occupational human exposure. This paper reviews some of the more recent findings on PCN occurrence in food, biota, and human tissues, and discusses the use of relative potencies to express PCN toxicity in foods.

Human Excretion of Polybrominated Diphenyl Ether Flame Retardants: Blood, Urine, and Sweat Study

Commonly used as flame retardants, polybrominated diphenyl ethers (PBDEs) are routinely detected in the environment, animals, and humans. Although these persistent organic pollutants are increasingly recognized as having serious health implications, particularly for children, this is the first study, to our knowledge, to investigate an intervention for human elimination of bioaccumulated PBDEs. Objectives. To determine the efficacy of blood, urine, and perspiration as PBDE biomonitoring mediums; assess excretion of five common PBDE congeners (28, 47, 99, 100, and 153) in urine and perspiration; and explore the potential of induced sweating for decreasing bioaccumulated PBDEs. Results. PBDE congeners were not found in urine samples; findings focus on blood and perspiration. 80% of participants tested positive in one or more body fluids for PBDE 28, 100% for PBDE 47, 95% for PBDE 99, and 90% for PBDE 100 and PBDE 153. Induced perspiration facilitated excretion of the five congeners, with different rates of excretion for different congeners. Conclusion. Blood testing provides only a partial understanding of human PBDE bioaccumulation; testing of both blood and perspiration provides a better understanding. This study provides important baseline evidence for regular induced perspiration as a potential means for therapeutic PBDE elimination. Fetotoxic and reproductive effects of PBDE exposure highlight the importance of further detoxification research.

Demographic and temporal trends of hexabromocyclododecanes (HBCDD) in an Australian population

Hexabromocyclododecanes (HBCDD) were measured in 67 pooled serum samples collected between 2002 and 2015 in South East Queensland, Australia. These data are the first report of HBCDD in Australian human serum. Temporal and demographic (age and gender) trends were investigated. HBCDD were detected in measurable concentrations in 69% of samples. The average ∑HBCDD concentration was 3.1ng/g lipid, whilst the range was <0.5 to 36ng/g lipid. α-HBCDD was the dominant stereoisomer making up an average of 60% of ∑HBCDD. The remainder was made up by γ-HBCDD. In contrast to another group of brominated flame retardants (BFRs, (polybrominated diphenyl ethers (PBDEs)), HBCDD were found in the lowest concentrations in pools from children aged 0-4 years. This could be attributed to differences in exposure, usage, and/ or the much lower half-life of HBCDD in the human body compared to PBDEs. HBCDD concentrations appear to be significantly higher in females than in males, however the reasons for this are unclear.

Novel brominated flame retardants in food composites and human milk from the Chinese Total Diet Study in 2011: Concentrations and a dietary exposure assessment

On the basis of the fifth Chinese total diet study (TDS) performed in 2011, the dietary exposure of the Chinese population to novel brominated flame retardants (NBFRs) was assessed. Six NBFRs were determined in 80 composite samples from four animal origin food groups and 29 pooled human milk samples. Based on gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS) analysis, the levels of the total NBFRs ranged from <LOD to 70.2ng/g lipid weight (lw) in food composites and from 2.48 to 23.9ng/g lw in human milk samples. Decabromodiphenyl ethane (DBDPE), with mean levels of 9.03ng/g lw in food composites and 8.06ng/g lw in human milk, was the most abundant compound in the total NBFRs. No obvious spatial distribution patterns in China were observed in food samples or human milk. The average estimated daily intake (EDI) of total NBFRs via food consumption for a "standard Chinese man" was 4.77ng/kg bodyweight (bw)/day, with a range of 0.681 to 18.9ng/kgbw/day. Meat and meat products were the main dietary source of NBFRs, although levels of NBFRs in aquatic food were found to be the highest among the four food groups. The average EDI of total NBFRs for nursing infants was 38.4ng/kgbw/day, with a range of 17.4 to 113ng/kgbw/day, which was approximately eight-fold higher than the EDI for adults, suggesting the heavy body burden of NBFRs on nursing infants. The levels and EDI of DBDPE in the present study were similar to or higher than those of legacy BFRs (i.e., PBDEs and HBCD) in the TDS 2007, indicating that DBDPE, as a main alternative to PBDEs, might have become the primary BFR used in China.