Tetra- and tribromophenoxyanisoles in marine samples from Oceania.
ABSTRACT Some methoxylated polybrominated diphenyl ethers (MeO-BDEs) are known halogenated natural products (HNPs) and are frequently detected in higher organisms of the marine environment. In this study we demonstrate that a prominent MeO-BDE, previously detected in marine mammals from Australia, is identical to 3,5-dibromo-2-(2',4'dibromo)phenoxyanisole (BC-3, 6-MeO-BDE 47). Up to 1.9 mg/ kg of 6-MeO-BDE 47 was present in cetaceans from Australia, 0.2-0.3 mg/kg in two crocodile eggs from Australia, but concentrations of 1 or 2 orders of magnitude lower were found in shark liver oil from NewZealand and in marine mammals from Africa and the Antarctic. Concentrations of 6-MeO-BDE 47 in samples from Australia were in the same range as anthropogenic pollutants such as PCB 153 and p,p'-DDE. Along with 6-MeO-BDE 47 and the known HNP 4,6-dibromo-2-(2',4'-dibromo)phenoxyanisole (BC-2, 2'-MeO-BDE 68), several tribromophenoxyanisoles (MeO-triBDE) were present in tissue of Australian cetaceans. To determine their structure, abiotic debromination experiments were performed using 6-MeO-BDE 47 and 2'-MeO-BDE 68 and superreduced dicyanocobalamine. These experiments resulted in formation of eight MeO-triBDEs, all of which were detected in the cetacean samples. Five of these eight MeO-triBDEs could be identified based on two standard compounds as well as gas chromatographic and mass spectrometric features. It was also shown that the first eluting isomer (compound 1), 6-MeO-BDE 17 (compound 2), and 2-MeO-BDE 39 (compound 5) were the most prominent MeO-triBDEs in the Australian cetacean samples. The concentrations of the MeO-triBDEs in two cetacean samples were 0.20 and 0.36 mg/kg, respectively. Although the reductive debromination with dicyanocobalamine resulted in a different congener pattern than was found in the marine mammals, it could not be excluded that the tribromo
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ABSTRACT: This paper reviews the available data on brominated flame retardants, the polybrominated diphenyl ethers (PBDEs), as well as on the naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in cetacean tissues around the world. Levels and possible sources of both compound classes are discussed. Odontocete cetaceans accumulate higher PBDE concentrations than mysticete species. PBDE contamination was higher in cetaceans from the Northern hemisphere, whereas MeO-PBDE levels were higher in animals from the Southern hemisphere. Southern resident killer whales from NE Pacific presented the highest levels reported in biota, followed by bottlenose dolphins from North Atlantic (U.K. and U.S. coast). Many species presented PBDE concentrations above threshold levels for health effects in odontocetes. Time trend studies indicate that PBDE concentrations in odontocetes from Japan, China, U.S. and Canada coastal zones have increased significantly over the past 30years. Studies from U.K. waters and NE Atlantic showed a decrease and/or stability of PBDE levels in cetacean tissues in recent decades. The highest MeO-PBDE concentrations were found in dolphins from Tanzania (Indian Ocean), bottlenose dolphins from Queensland, Australia (SW Pacific), and odontocetes from coastal and continental shelf waters off southeastern Brazil (SW Atlantic). The upwelling phenomenon and the presence of coral reef complexes in these tropical oceans may explain the large amounts of the naturally-produced organobromines. Considering that these bioaccumulative chemicals have properties that could cause many deleterious effects in those animals, future studies are required to evaluate the potential ecotoxicological risks.Science of The Total Environment 03/2014; 481C:619-634. · 3.16 Impact Factor
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