Neutral and phenolic brominated organic compounds of natural and anthropogenic origin in northeast Atlantic Greenland shark (Somniosus microcephalus)

Abstract

In the present study, muscle and liver tissue from 10 female Greenland sharks (Somniosus microcephalus) collected in Icelandic waters were analyzed for neutral and phenolic brominated organic compounds, including polybrominated diphenyl ethers (PBDEs) and the structurally related methoxylated (MeO) and hydroxylated (OH) PBDEs. Hydroxylated PBDEs exist both as natural products and as metabolites of the anthropogenic PBDEs, whereas MeO‐PBDEs appear to exclusively be of natural origin. Other compounds examined were 2′,6‐dimethoxy‐2,3′,4,5′‐tetrabromodiphenyl ether (2′,6‐diMeO‐BDE68), 2,2′‐dimethoxy‐3,3′,5,5′‐tetrabromobiphenyl (2,2′‐diMeO‐BB80), 2,4,6‐tribromoanisol (2,4,6‐TBA) and 2,4,6‐tribromophenol, all of natural origin, although 2,4,6‐TBA and its phenolic counterpart may also be of anthropogenic origin. The major brominated organic compound was 6‐MeO‐BDE47, and ΣMeO‐PBDE ranged from 49 to 210 ng/g fat in muscle and from 55 to 200 ng/g fat in liver tissue. Total concentrations of PBDEs were lower than ΣMeO‐PBDE, in all but one sample, ranging between 7.3 to 190 and 9.9 to 200 ng/g fat in muscle and liver, respectively, and major congeners were BDE‐47, BDE‐99, and BDE‐100. Polybrominated diphenyl ethers were analyzed using both high‐ and low‐resolution mass spectrometry (MS) as a quality assurance, and the results from this comparison were acceptable. In accordance with previous work on Greenland sharks, no size/age‐related accumulation was observed. Differences seen in concentrations were instead assumed to be a reflection of different feeding habits among the individuals. Phenolic compounds were only formed/retained in trace amounts in the Greenland shark. Among the phenolic compounds studied were 6‐OH‐BDE47, 2′‐OH‐BDE68, and 2,4,6‐tribromophenol, all detected in liver and the latter two in muscle. Environ. Toxicol. Chem. 2010;29:2653–2659. © 2010 SETAC