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| 2. |
- Athanasiadou, Maria, et al.
(author)
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Polybrominated diphenyl ethers (PBDEs) and bioaccumulative hydroxylated PBDE metabolites in young humans from Managua, Nicaragua.
- 2008
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In: Environ Health Perspect. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 116:3, s. 400-8
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Our aim was to investigate exposure to polybrominated diphenyl ethers (PBDEs) in a young urban population in a developing country, with focus on potentially highly exposed children working informally as scrap scavengers at a large municipal waste disposal site. We also set out to investigate whether hydroxylated metabolites, which not hitherto have been found retained in humans, could be detected. METHODS: We assessed PBDEs in pooled serum samples obtained in 2002 from children 11-15 years of age, working and sometimes also living at the municipal waste disposal site in Managua, and in nonworking urban children. The influence of fish consumption was evaluated in the children and in groups of women 15-44 years of age who differed markedly in their fish consumption. Hydroxylated PBDEs were assessed as their methoxylated derivates. The chemical analyses were performed by gas chromatography/mass spectrometry, using authentic reference substances. RESULTS: The children living and working at the waste disposal site showed very high levels of medium brominated diphenyl ethers. The levels observed in the referent children were comparable to contemporary observations in the United States. The exposure pattern was consistent with dust being the dominating source. The children with the highest PBDE levels also had the highest levels of hydroxylated metabolites. CONCLUSIONS: Unexpectedly, very high levels of PBDEs were found in children from an urban area in a developing country. Also, for the first time, hydroxylated PBDE metabolites were found to bioaccumulate in human serum.
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| 3. |
- Christiansson, Anna, et al.
(author)
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Methods for synthesis of nonabromodiphenyl ethers and a chloro-nonabromodiphenyl ether
- 2006
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In: Chemosphere. ; 63:4, s. 562-569
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Journal article (peer-reviewed)abstract
- Polybrominated diphenyl ethers (PBDEs) have been used extensively as brominated flame retardants (BFRs) in textiles, upholstery and electronics. They are ubiquitous contaminants in wildlife and humans. A low concentration of nonabrominated diphenyl ethers (nonaBDEs) is present in commercial DecaBDE and they are also abiotic and biotic debromination products of decabromodiphenyl ether (BDE-209). The objective of the present work was to develop methods for synthesis of the three nonaBDEs, 2,2',3,3',4,4',5,5',6-nonabromodiphenyl ether (BDE-206), 2,2',3,3',4,4',5,6,6'-nonabromodiphenyl ether (BDE-207) and 2,2',3,3',4,5,5',6,6'-nonabromodiphenyl ether (BDE-208), with the intention of making them available as authentic standards for analytical, toxicological and stability studies, as well as studies regarding physical-chemical properties. Two methods were developed, one based on perbromination of phenoxyanilines and the other via reductive debromination of BDE-209 by sodium borohydride followed by chromatographic separation of the three nonaBDE isomers formed. An additional nonabrominated compound, 4'-chloro-2,2',3,3',4,5,5',6,6'-nonabromodiphenyl ether (Cl-BDE-208), was also synthesized in the present work. Cl-BDE-208, prepared by the perbromination of 4-chlorodiphenyl ether, may be used as an internal standard in analysis of highly brominated diphenyl ethers. BDE-206, BDE-207, BDE-208 and Cl-BDE-208 were characterized by 1H NMR, 13C NMR, electron ionization mass spectra and by their melting points. The structures of all three nonaBDEs have been characterized previously by X-ray crystallography.
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| 4. |
- Dahlberg, Anna-Karin, 1985-
(author)
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Environmentally relevant chemical disruptors of oxidative phosphorylation in Baltic Sea biota : Exposure and toxic potentials
- 2015
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Doctoral thesis (other academic/artistic)abstract
- This thesis focuses on toxicity and occurrence of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in Baltic Sea biota. The aims were to assess OH-PBDEs potency for disruption of oxidative phosphorylation (OXPHOS) and determine their and related compounds exposure in Baltic blue mussel, herring and long-tailed duck. A method for analysis of OH-PBDEs in herring and long-tailed duck plasma was also evaluated.Relevant OH-PBDEs were tested in vitro for OXPHOS disruption, using a classic rat mitochondrial respiration assay and a cell mitochondrial membrane potential assay. All compounds were found to disrupt OXPHOS either by protonophoric uncoupling and/or via inhibition of the electron transport chain. 6-OH-BDE47 and 6-OH-BDE85, were identified as particularly potent OXPHOS disruptors. Strong synergism was observed when OH-PBDEs were tested as a mixture corresponding to what is present in Baltic blue mussels.Baltic blue mussel is main feed for several species of mussel feeding sea ducks which have decreased dramatically in numbers. To assess long-tailed ducks exposure to brominated substances, liver tissue from long-tailed ducks wintering in the Baltic Sea and blue mussels were analysed. The result confirms that long-tailed duck are exposed to OH-PBDEs via their diet. However, low concentrations were found in the duck livers, which suggest low retention of these compounds despite daily intake. How the nutritional value of blue mussels as feed for sea ducks are affected by OH-PBDE exposure still needs further studies. Other species of sea ducks foraging on Baltic blue mussels during summer months can also be more exposed due to seasonal variation in primary production.Herring sampled in the Baltic Proper and Bothnian Sea, were found to contain OH-PBDEs and high levels of their methylated counterpart, MeO-PBDEs. As demethylation of MeO-PBDEs is known to occur in fish, MeO-PBDEs may pose as additional source for more toxic OH-PBDEs in herring and their roe.
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| 5. |
- Eriksson, Johan, et al.
(author)
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Photochemical decomposition of fifteen polybrominated diphenyl ether congeners in methanol/water
- 2004
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In: Environmental Science & Technology. - : American Chemical Society. - 1520-5851 .- 0013-936X. ; 38:11, s. 3119-3125
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Journal article (peer-reviewed)abstract
- Among all brominated flame retardants in use, the polybrominated diphenyl ethers (PBDEs) have been identified as being of particular environmental concern due to their global distribution and bioaccumulating properties, as observed in humans and wildlife worldwide. Still there is a need for more data on the basic characteristics of PBDEs to better understand and describe their environmental fate. Hence, the aim of this study was to investigate the photochemical degradation of PBDEs with different degrees of bromination. The photochemical degradation of 15 individual PBDEs substituted with 4−10 bromine atoms was studied in methanol/water (8:2) by UV light in the sunlight region. Nine of these were also studied in pure methanol, and four of the nine PBDEs were studied in tetrahydrofuran. The photochemical reaction rate decreased with decreasing number of bromine substituents in the molecule but also in some cases influenced by the PBDE substitution pattern. The reaction rate was dependent on the solvent in such a way that the reaction rate in a methanol/water solution was consistently around 1.7 times lower than in pure methanol and 2−3 times lower than in THF. The UV degradation half-life of decaBDE (T1/2 = 0.5 h) was more than 500 times shorter than the environmentally abundant congener 2,2‘,4,4‘-tetraBDE (T1/2 = 12 d) in methanol/water. The quantum yields in the methanol/water solution ranged from 0.1 to 0.3. The photochemical reaction of decaBDE is a consecutive debromination from ten- down to six-bromine-substituted PBDEs. Products with less than six bromines were tentatively identified as brominated dibenzofurans and traces of what was indicated as methoxylated brominated dibenzofurans.
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| 6. |
- Houde, Magali, et al.
(author)
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POLYBROMINATED DIPHENYL ETHERS AND THEIR HYDROXYLATED ANALOGS IN PLASMA OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) FROM THE UNITED STATES EAST COAST.
- 2009
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In: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 28:10, s. 2061-2068
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Journal article (peer-reviewed)abstract
- Polybrominated diphenyl ethers (PBDEs) and hydroxylated-PBDEs (OH-PBDE) were determined in plasma of free-ranging bottlenose dolphins (Tursiops truncatus) from Charleston (CHS), South Carolina, and the Indian River Lagoon (IRL), Florida, US. Significantly lower sum (Sigma) of PBDE concentrations (sum of 12 congeners) were found in animals from the IRL [arithmetic mean: 5.454.63 ng/g wet weight (ww)] compared to CHS (3040 ng/g ww). BDE-47 was the predominant PBDE in dolphins from the IRL (50% of the SigmaPBDEs) and CHS (58%). SigmaPBDE concentrations in plasma of dolphins were negatively correlated with age at both locations. Fifteen and sixteen individual OH-PBDE congeners could be quantified in plasma of dolphins from IRL and CHS, respectively. Similar to SigmaPBDE, mean SigmaOH-PBDE concentrations were significantly higher in plasma of dolphins at CHS (1150708 pg/g ww) compared to IRL (624393 pg/g ww). The predominant congener at both locations was 6-OH-PBDE 47 (IRL: 384319 pg/g ww; CHS: 541344 pg/g ww) representing 61.5% of total SigmaOH-PBDE at IRL and 47.0% at CHS. Concentrations of SigmaOH-PBDEs were weakly negatively correlated with age in dolphins from both locations (P<0.05; IRL, R2=0.048; CHS, R2=0.021). In addition to the OH-PBDE congeners identified with technical standards, eight and four unidentified OH-PBDEs were detected and quantified respectively in animals from CHS (sum of unidentified OH-PBDEs=1.350.90 pg/g ww) and IRL (0.730.40 pg/g ww). Our results suggest that, unlike OH-PCBs, OH-PBDEs in bottlenose dolphins are minor products in plasma relative to SigmaPBDEs and a significant proportion may be a consequence of the dietary uptake of naturally produced methoxylated- and OH-PBDEs.
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| 7. |
- Legradi, Jessica, et al.
(author)
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Disruption of oxidative phosphorylation (OXPHOS) by hydroxylated polybrominated diphenyl ethers (OH-PBDEs) present in the marine environment
- 2014
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 48:24, s. 14703-14711
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Journal article (peer-reviewed)abstract
- Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are of growing concern, as they have been detected in both humans and wildlife and have been shown to be toxic. Recent studies have indicated that OH-PBDEs can be more toxic than PBDEs, partly due to their ability to disrupt oxidative phosphorylation (OXPHOS), an essential process in energy metabolism. In this study, we determined the OXPHOS disruption potential of 18 OH-PBDE congeners reported in marine wildlife using two in vitro bioassays, namely the classic rat mitochondrial respiration assay, and a mitochrondrial membrane potential assay using zebrafish PAC2 cells. Single OH-PBDE congeners as well as mixtures were tested to study potential additive or synergistic effects. An environmental mixture composed of seven OH-PBDE congeners mimicking the concentrations reported in Baltic blue mussels were also studied. We report that all OH-PBDEs tested were able to disrupt OXPHOS via either protonophoric uncoupling and/or inhibition of the electron transport chain. Additionally we show that OH-PBDEs tested in combinations as found in the environment have the potential to disrupt OXPHOS. Importantly, mixtures of OH-PBDEs may show very strong synergistic effects, stressing the importance of further research on the in vivo impacts of these compounds in the environment
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| 8. |
- Malmberg, Tina, et al.
(author)
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Retention of hydroxylated PBDE metabolites in blood plasma from PBDE exposed rats
- 2005
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In: Environmental Science and Technology. - 0013-936X .- 1520-5851. ; 39:14, s. 5342-5348
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Journal article (peer-reviewed)abstract
- 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 parapositions. 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.
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