A Review of Hydroxylated and Methoxylated Brominated Diphenyl Ethers in Marine Environments

Abstract

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) are present in the marine environment worldwide. Both OH-PBDEs and MeO-PBDEs are known natural products, whereas OH-PBDEs may also be metabolites of PBDEs. There is growing concern regarding OH-PBDEs as these compounds seem to be biological active than PBDEs. In the present study, we reviewed the available data on the contamination of OH/MeO-PBDEs in the marine environment worldwide, including seawater, marine sediment, marine plants, invertebrates, fish, seabirds and mammals. Bioaccumulation and biomagnification of OH/MeO-PBDEs in the marine food web were summarized as well. This study also proposes the future research of OH/MeO-PBDEs, including the production and the synthesis pathway of OH/MeO-PBDEs, the toxicokinetics of OH/MeO-PBDEs and the toxicology and human exposure risk assessment.

Temporal Trends and Suspect Screening of Halogenated Flame Retardants and Their Metabolites in Blubbers of Cetaceans Stranded in Hong Kong Waters during 2013–2020

“…Two MeO-penta-BDE isomers in porpoise and dolphin samples with RTs of 8.23 and 10.47 min were screened using their [M – Br + O] − fragment with diagnostic ions of 528.7127 (C 13 H 7 79 Br 3 81 BrO 3 − ; mass error = 2.6 ppm), 530.7103 (C 13 H 7 79 Br 2 81 Br 2 O 3 − ; mass error = 1.8 ppm), and 532.7075 (C 13 H 7 79 Br 81 Br 3 O 3 − ; mass error = 0.5 ppm) with isotope intensity ratios of 69:100:65. MeO- and OH-BDEs are not manufactured; however, they can be naturally formed in marine organisms. , It was reported that OH-BDEs did not biomagnify in the marine food web, and OH-BDEs in marine mammals mainly originate from (1) metabolism of PBDEs and/or MeO-BDEs and (2) the direct uptake from the natural source. − A significant positive correlation was found between concentrations of OH-tetra-BDE and BDE-47/MeO-tetra-BDE in both porpoises and dolphins ( p < 0.05; Table S6), suggesting that the indirect source (i.e., metabolism of PBDEs and/or MeO-BDEs) could be the main origin for OH-tetra-BDE in the investigated cetaceans. MeO-BDEs were reported to have biomagnification potential, and MeO-BDEs present in marine mammals were generally considered to come from natural sources. − Nevertheless, a significant positive correlation was observed between concentrations of MeO-BDEs and native PBDEs in both porpoises and dolphins ( p < 0.05; Table S6), indicating the possible contribution of the biotransformation of PBDEs to MeO-BDEs in the investigated marine mammals.…”

“…MeO- and OH-BDEs are not manufactured; however, they can be naturally formed in marine organisms. , It was reported that OH-BDEs did not biomagnify in the marine food web, and OH-BDEs in marine mammals mainly originate from (1) metabolism of PBDEs and/or MeO-BDEs and (2) the direct uptake from the natural source. − A significant positive correlation was found between concentrations of OH-tetra-BDE and BDE-47/MeO-tetra-BDE in both porpoises and dolphins ( p < 0.05; Table S6), suggesting that the indirect source (i.e., metabolism of PBDEs and/or MeO-BDEs) could be the main origin for OH-tetra-BDE in the investigated cetaceans. MeO-BDEs were reported to have biomagnification potential, and MeO-BDEs present in marine mammals were generally considered to come from natural sources. − Nevertheless, a significant positive correlation was observed between concentrations of MeO-BDEs and native PBDEs in both porpoises and dolphins ( p < 0.05; Table S6), indicating the possible contribution of the biotransformation of PBDEs to MeO-BDEs in the investigated marine mammals. The origin of MeO-BDEs in marine cetaceans is likely to be attributed to both natural source and PBDE metabolism, which deserves future investigation.…”

High Amounts of Halogenated Natural Products in Sperm Whales (Physeter macrocephalus) from Two Italian Regions in the Mediterranean Sea

“…For instance, OH-PBDEs were found to bioaccumulate less likely than PBDEs or MeO-BDEs. 43 Likewise, OH-PCBs were only detected in the plasma but not the blubber of harbor seals ( Phoca vitulina ). 44 Also, the present sample cleanup method (and assumedly others as well) does not cover hydroxylated compounds such as bromophenols, which require a more polar solvent for their elution ( section 2.3 ).…”

“…In this context it is important to note that the high amounts of a hydroxylated polyhalogenated compound in the blubber of marine mammals were surprising. For instance, OH-PBDEs were found to bioaccumulate less likely than PBDEs or MeO-BDEs . Likewise, OH-PCBs were only detected in the plasma but not the blubber of harbor seals ( Phoca vitulina ) .…”

Thyroid Hormone Receptor Agonistic and Antagonistic Activity of Newly Synthesized Dihydroxylated Polybrominated Diphenyl Ethers: An In Vitro and In Silico Coactivator Recruitment Study

“…Agarwal et al [ 11 ] reported marine bacteria as producers of OH-PBDEs and established a genetic and molecular foundation for their production. Now, it is widely believed the OH-PBDEs in the food chain mainly come from the biosynthesis of ocean microorganisms rather than commercial PBDE products [ 12 ] In our previous investigation, OH/diOH-PBDEs were also detected in sea fish available in markets, indicating the potential risk of human exposure to these compounds [ 13 ].…”