Anthropogenic and Naturally Occurring Organobrominated Compounds in Two Deep-Sea Fish Species from the Mediterranean Sea

Polybrominated diphenyl ethers (PBDEs) were investigated in 15 composite liver samples from two deep-sea fish species, the hollowsnout grenadier (Trachyrinchus trachyrinchus, TT) and the roughsnout grenadier (Coelorhynchus coelorynchus, CC). Mean concentrations of sum tri- to hepta-BDEs were higher in CC species than in the TT species (16.9 vs 4.5 ng/g lipid weight (lw), respectively). BDE 47 and BDE 100 were the major congeners in both species. Methoxylated PBDEs (MeO-PBDEs), reported as being naturally produced in marine environments, were also measured in all samples. Similar to those of PBDEs, mean concentrations of sum MeO-PBDEs (sum congeners 2'-MeO-BDE 68 and 6-MeO-BDE 47) were higher in the CC species (28.9 vs 6.6 ng/g lw, respectively). Interestingly, polybrominated hexahydroxanthene derivatives (PBHDs) had the highest contribution to the total load of organobromines in the deep-sea fish samples. Contrary to those of PBDEs and MeO-PBDEs, the mean concentrations of PBHDs were higher in the TT species (7040 vs 530 ng/g lw, respectively). Furthermore, an unusual profile was seen in the TT species, for which a tetrabrominated BHD isomer was the predominant isomer (up to 98% of the sum PBHDs). This differs from the profiles of PBHDs dominated by a tribrominated BHD isomer reported until now in the literature. The mixed halogenated monoterpene (MHC-1) and 2,4,6-tribromoanisole (TBA) were detected as well, albeit at lower concentration (<5 ng/g lw), supporting the hypothesis that these two natural products are rather abundant in shallow waters.