The San Antonio Statement on Brominated and Chlorinated Flame Retardants addresses the growing concern in the scientific community about the persistent, bioaccumulative, and toxic properties of ...brominated and chlorinated organic flame retardants (BFRs and CFRs, respectively) and the exposure to humans and wildlife as a result of intensive use. Nearly 150 scientists from 22 countries have signed the statement since it was presented at the 30th International Symposium on Halogenated Persistent Organic Pollutants (Dioxin 2010), held 1217 September 2010 in San Antonio, Texas. The scientist signatories are experts on the health effects and environmental fate of BFRs and CFRs and environmental contaminants in general. The International Panel on Chemical Pollution (IPCP), an international network of scientists working on various aspects of chemical pollution, also has approved the statement.
Methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and hydroxylated PBDEs (OH-PBDEs) have recently been identified in fish and wildlife from the Baltic Sea. Both OH-PBDEs and MeO-PBDEs are known ...natural products, while OH-PBDEs also may be metabolites of PBDEs. The aim of the present study was to determine if the red macroalga Ceramium tenuicorne could be a source for MeO- and OH-PBDEs in the Baltic environment. Blue mussels (Mytilus edulis) from the same area were also investigated for their content of MeO- and OH-PBDEs. Seven OH-PBDEs and four MeO-PBDEs were present both in the red macroalga and the blue mussels. The mussels also contained a monochlorinated OH-tetraBDE. One of the compounds, 6-methoxy-2,2‘,3,4,4‘,5-hexabromodiphenyl ether, has never been reported to occur in the environment. The identification was based on comparison of relative retention times with reference standards, on two gas chromatographic columns of different polarities, together with comparisons of full-scan electron capture negative ionization (ECNI) and electron ionization (EI) mass spectra. It is shown that MeO-PBDEs and OH-PBDEs are present in algae, but at this stage it could not be confirmed if the compounds are produced by the alga itself or by its associated microflora and/or microfauna.
Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been identified as metabolites of PBDEs, and also as compounds of natural origin in the marine environment; however, there has only been ...very limited study of their presence in the abiotic environment. In the present study, OH-PBDEs were determined in samples of surface water and precipitation (rain and snow) collected from sites in Ontario, Canada. OH-PBDEs were detected in all the samples analyzed, although half of the observed peaks did not correspond to any of the 18 authentic standards available. Fluxes of ΣOH-PBDEs ranged from 3.5 to 190 pg/m2 in snow and from 15 to 170 pg/m2/day in rain, and those were higher at three of the southern Ontario locations relative to a single northern remote site. Concentrations of ΣOH-PBDEs ranged from 2.2 to 70 pg/L in water and from <1 to 420 pg/g in particulate organic carbon (POC), and higher values were found near sewage treatment plant (STP) outfalls in Lake Ontario. Partition coefficients (log K oc) for OH-PBDEs ranged from 4.0 to 5.1. The results in this study suggest that OH-PBDEs are ubiquitous in the abiotic environment and most likely are produced through reaction of PBDEs with atmospheric OH radicals. As well, they may be present in surface waters near STPs due to oxidation of PBDEs and inflows from metabolism by humans and animals.
Background, aim, and scope Decabromodiphenyl ether (DecaBDE) is used as an additive flame retardant in polymers. It has become a ubiquitous environmental contaminant, particularly abundant in abiotic ...media, such as sediments, air, and dust, and also present in wildlife and in humans. The main DecaBDE constituent, perbrominated diphenyl ether (BDE-209), is susceptible to transformations as observed in experimental work. This work is aimed at identifying and assessing the relative amounts of products formed after UV irradiation of BDE-209. Materials and methods BDE-209, dissolved in tetrahydrofuran (THF), methanol, or combinations of methanol/water, was exposed to UV light for 100 or 200 min. Samples were analyzed by gas chromatography/mass spectrometry (electron ionization) for polybrominated diphenyl ethers (PBDEs), dibenzofurans (PBDFs), methoxylated PBDEs, and phenolic PBDE products. Results The products formed were hexaBDEs to nonaBDEs, monoBDFs to pentaBDFs, and methoxylated tetraBDFs to pentaBDFs. The products found in the fraction containing halogenated phenols were assigned to be pentabromophenol, dihydroxytetrabromobenzene, dihydroxydibromodibenzofuran, dihydroxytribromodibenzofuran, and dihydroxytetrabromodibenzofuran. The PBDEs accounted for approximately 90% of the total amount of substances in each sample and the PBDFs for about 10%. Discussion BDE-209 is a source of PBDEs primarily present in OctaBDEs but also to some extent in PentaBDEs, both being commercial products now banned within the EU and in several states within the USA. It is notable that OH-PBDFs have not been identified or indicated in any of the photolysis studies performed to date. Formation of OH-PBDFs, however, may occur as pure radical reactions in the atmosphere. Conclusions Photolysis of decaBDE yields a wide span of products, from nonaBDEs to hydroxylated bromobenzenes. It is evident that irradiation of decaBDE in water and methanol yields OH-PBDFs and MeO-PBDFs, respectively. BDE-202 (2,2',3,3',5,5',6,6'-octabromodiphenyl ether) is identified as a marker of BDE-209 photolysis. Recommendations and perspectives BDE-209, the main constituent of DecaBDE, is primarily forming debrominated diphenyl ethers with higher persistence which are more bioaccumulative than the starting material when subjected to UV light. Hence, DecaBDE should be considered as a source of these PBDE congeners in the environment.
Background: Oxidative metabolism, resulting in the formation of hydroxylated polybrominated diphenyl ether (PBDE) metabolites, may enhance the neurotoxic potential of brominated flame retardants. ...Objective: Our objective was to investigate the effects of a hydroxylated metabolite 2,2',4,4'-tetrabromodiphenyl ether (BDE-47; 6-OH-BDE-47) on changes in the intracellular ${\rm Ca}^{2+}$ concentration $({\rm Ca}^{2+}_{i})$ and vesicular catecholamine release in PC12 cells. Methods: We measured vesicular catecholamine release and ${\rm Ca}^{2+}_{i}$ using amperometry and imaging of the fluorescent ${\rm Ca}^{2+}\text{-sensitive}$ dye Fura-2, respectively. Results: Acute exposure of PC12 cells to 6-OH-BDE-47 (5 μM) induced vesicular catecholamine release. Catecholamine release coincided with a transient increase in ${\rm Ca}^{2+}_{i}$, which was observed shortly after the onset of exposure to 6-OH-BDE-47 (120 μM). An additional late increase in ${\rm Ca}^{2+}_{i}$ was often observed at ≥ 1 μM 6-OH-BDE-47. The initial transient increase was absent in cells exposed to the parent compound BDE-47, whereas the late increase was observed only at 20 μM. Using the mitochondrial uncoupler carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) and thapsigargin to empty intracellular ${\rm Ca}^{2+}$ stores, we found that the initial increase originates from emptying of the endoplasmic reticulum and consequent influx of extracellular ${\rm Ca}^{2+}$, whereas the late increase originates primarily from mitochondria. Conclusion: The hydroxylated metabolite 6-OH-BDE-47 is more potent in disturbing ${\rm Ca}^{2+}$ homeostasis and neurotransmitter release than the parent compound BDE-47. The present findings indicate that bioactivation by oxidative metabolism adds considerably to the neurotoxic potential of PBDEs. Additionally, based on the observed mechanism of action, a cumulative neurotoxic effect of PBDEs and ortho-substituted polychlorinated biphenyls on ${\rm Ca}^{2+}_{i}$ cannot be ruled out.
Brominated flame retardants (BFRs) are persistent and ubiquitous chemicals in the environment, and they are found at increasing levels in tissues of wildlife and humans. Previous in vitro studies ...with the BFR class of polybrominated diphenyl ethers (BDEs) have shown endocrine-disrupting properties. Our study assessed the potential effects of nineteen BDEs, five hydroxylated BDEs (OH-BDEs), one methoxylated BDE (CH3O-BDE), tetrabromobisphenol-A (TBBPA), its dibromopropane ether derivative (TBBPA-DBPE), and the brominated phenols/anisols 2,4,6-tribromophenol (TBP), 4-bromophenol (4BP) and 2,4,6-tribromoanisole (TBA) on the catalytic activity of the steroidogenic enzyme aromatase (CYP19) in H295R human adrenocortical carcinoma cells. Effects were studied in the concentration range from 0.5 to 7.5 μM; exposures were for 24 h. Both 6-OH-BDE47 and 6-OH-BDE99 showed an inhibitory effect on aromatase activity at concentrations >2.5 μM and >5 μM, respectively. However, 6-OH-BDE47 also caused a statistically significant increase in cytotoxicity (based on mitochondrial MTT reduction and lactate dehydrogenase-leakage LDH) at concentrations >2.5 μM that could explain in part the apparent inhibitory effect on aromatase activity. Compared to 6-OH-BDE47, the methoxy analog (6-CH3O-BDE47) did not elicit a cytotoxic effect, whereas significant inhibition of aromatase remained. TBP caused a concentration-dependent induction of aromatase activity between 0.5 and 7.5 μM (with a maximum of 3.8-fold induction at 7.5 μM). This induction was not observed when a OH– group replaced the CH3O– group or when bromine atoms adjacent to this OH– group were absent. These in vitro results provide a basis for studies of more detailed structure–activity relationships between these brominated compounds and the modulation of aromatase activity.
Commercial decabromodiphenyl ether (DecaBDE) is commonly used as a flame retardant in different electrical and textile applications. It is also used in the production of flame-retarded rubber ...compound. DecaBDE is the major technical polybrominated diphenyl ether (PBDE) in use today and consists mainly of decabromodiphenyl ether (BDE-209). PBDEs, including BDE-209, are well-known environmental pollutants, ubiquitous both in aquatic and terrestrial environments. The aim of the present study was to assess the exposure to PBDEs in workers manufacturing or handling rubber which was flame retarded with DecaBDE. A referent group, abattoir workers (slaughterhouse workers), with no occupational exposure to PBDEs, was also investigated. Moreover, the methodology for analysis of PBDEs in serum was refined, with special emphasis on congeners with a high number of bromine substituents, i.e., octa- to decaBDEs. The highest BDE-209 concentration observed among the rubber workers was 280 pmol/g lipid weight (l.w.) (270 ng/g l.w.). The median concentration of BDE-209 among rubber workers was 37 pmol/g l.w. (35 ng/g l.w.). Among referents, the median was 2.5 (range 0.92−9.7) pmol/g l.w. (median 2.4 ng/g l.w.). In rubber workers the BDE-209 concentrations were up to 32% (median 4%) of the 2,2‘,4,4‘,5,5‘-chlorobiphenyl (CB-153) concentra tions, on a molar basis, whereas the referents had BDE-209 concentrations which were similar to that of 2,2‘,4,4‘-bromodiphenyl ether (BDE-47), below 1.4% (median 0.3%) of the CB-153 concentration. Concentrations of all nonabromodiphenyl ethers (nonaBDEs) and several octabrmodiphenyl ethers (octaBDEs) congeners, including BDE-203, were also elevated among the rubber workers, with 2.5- to 11-fold higher median concentrations, compared to the referents. The results confirm a significant uptake of BDE-209 in the workers exposed to DecaBDE and indicate a potential for in vivo formation of lower BDEs in these persons.
Evidence has accumulated that exposure to widespread environmental toxicants, such as heavy metals, persistent organic pollutants, and tobacco smoke adversely affect fetal development and organ ...maturation, even after birth. The developing immune and respiratory systems are more sensitive to environmental toxicants due to their long-term physical development, starting from the early embryonic stage and persisting into early postnatal life, which requires complex signaling pathways that control proliferation and differentiation of highly heterogeneous cell types. In this review, we summarize the effect of early-life exposure to several widespread environmental toxicants on immune and lung development before and after birth, including the effects on immune cell counts, baseline characteristics of cell-mediated and humoral immunity, and alteration of lung structure and function in offspring. We also review evidence supporting the association between early-life exposure to environmental toxicants and risk for immune-related diseases and lung dysfunction in offspring in later life.
Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental contaminants due to their use as flame retardants. Similarly to PCBs, the PBDEs are metabolized to hydroxylated metabolites ...(OH-PBDEs) in mammals. In the present study equimolar doses of seven environmentally relevant PBDE congeners were given intraperitoneally as a mixture to rats, and their blood plasma was analyzed for parent compounds and hydroxylated metabolites 1 and 5 days after dosing. Sixteen OH-PBDEs and two diOH-PBDEs were detected as PBDE metabolites in the rat plasma, a novel finding. Four OH-tetraBDEs were structurally identified by comparison (gas chromatography/mass spectrometry) with authentic reference standards. The position of the hydroxyl groups was suggested according to the mass spectrometric fragmentation patterns of the corresponding PBDE methyl ether derivatives. The OH-PBDE metabolites were dominated by hydroxyl groups in the meta- and para-positions. The results show that OH-PBDE congeners have an ability to be retained in rat blood, most likely by a mechanism similar to that of OH-PCBs. The results will be useful for determination of the origin of OH-PBDEs present in wildlife and in humans, since OH-PBDEs are also common natural products in marine environments.
Methoxylated and hydroxylated polybrominated diphenyl ethers (MeO-PBDEs and OH-PBDEs) have recently been reported to be present in wildlife from Northern Europe. The structures of a majority of these ...compounds have however been unknown. In the present study, nine OH-PBDEs and six MeO-PBDEs were identified in Baltic Sea salmon (Salmo salar) blood. All OH- and MeO-PBDEs identified were substituted with four or five bromines, and five of these had one chlorine substituent. Fourteen of the OH- and MeO-PBDEs have the methoxy or hydroxy group substituted in the ortho position to the diphenyl ether bond. Identification was done by comparison of relative retention times of authentic reference standards with compounds present in salmon plasma on two gas chromatographic columns of different polarities. The identification was supported by comparisons of full-scan mass spectrometric data: electron ionization (EI) and electron capture negative ionization (ECNI). Nine of the 15 OH- and MeO-PBDEs identified have not previously been reported to occur in the environment. The structures of several identified OH- and MeO-PBDEs support natural origin. However, at least one of the OH-PBDEs may be a hydroxylated metabolite of anthropogenic polybrominated diphenyl ether (PBDE).
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