Identification of Hydroxylated Polybrominated Diphenyl Ether Metabolites in Blood Plasma from Polybrominated Diphenyl Ether Exposed Rats

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.

Levels and distribution of methoxylated and hydroxylated polybrominated diphenyl ethers in plant and soil samples surrounding a seafood processing factory and a seafood market

“…These orthosubstituted OH-PBDEs and MeO-PBDEs have been structurally identified and confirmed as natural compounds (Malmvarn et al, 2005(Malmvarn et al, , 2008. The meta-and para-substituted OH-PBDEs have been reported to be biotransformation products produced during PBDE exposure (Malmberg et al, 2005;Marsh et al, 2006;Qiu et al, 2007). Recently, Wan et al demonstrated the interconversion of OH-PBDE and MeO-PBDE in Japanese medaka (Wan et al, 2010).…”

Hydroxylated PBDEs and brominated phenolic compounds in particulate matters emitted during recycling of waste printed circuit boards in a typical e-waste workshop of South China

“…Several compounds, assigned to be mono-OH-PBDEs and di-OH-PBDEs were also detected, however, their structures could not be identified in the present study because of an absence of authentic standards. It is suggested that meta-methoxysubstituted PBDEs does not contain fragment ions of [MÀCH 3 (Malmberg et al, 2005;Marsh et al, 2004). Therefore, position of the hydroxylated group in the unidentified monohydroxylated PBDE congeners was suggested based on the characteristic fragmentation pattern of their EI mass spectra.…”

“…It was reported that OH-PBDE metabolites from laboratory studies in animals were dominated by hydroxyl groups in the meta or para positions (Malmberg et al, 2005;Marsh et al, 2006;Qiu et al, 2007). Ortho OH-substituted OH-PBDEs have been identified as naturally occurring formulations in marine organisms such as sponges, tunicates, and algae (Fu et al, 1995;Malmvarn et al, 2005;Unson et al, 1994).…”

“…Hydroxylated PBDEs (OH-PBDEs), which are a relatively new group of phenolic compounds, have been detected in biological samples including fish (Marsh et al, 2004;Valters et al, 2005), algae (Malmvarn et al, 2005(Malmvarn et al, , 2008, birds (Verreault et al, 2005), rats and mice (Malmberg et al, 2005;Qiu et al, 2007), as well as human blood Qiu et al, 2009;Yu et al, 2010). It has been shown that OH-PBDEs can be naturally formed in marine algae or by their associated microorganisms (Malmvarn et al, 2005(Malmvarn et al, , 2008Unson et al, 1994).…”

“…It has been shown that OH-PBDEs can be naturally formed in marine algae or by their associated microorganisms (Malmvarn et al, 2005(Malmvarn et al, , 2008Unson et al, 1994). Studies in animals suggest that OH-PBDEs are metabolic products of PBDEs (Hamers et al, 2008;Malmberg et al, 2005;Stapleton et al, 2009). Recently, it also has been suggested that demethylation of naturally produced methoxylated PBDEs (MeO-PBDEs) may result in OH-PBDEs in the environment (Wan et al, , 2009Wiseman et al, 2011).…”