Polybrominated diphenyl ethers and their methoxylated and hydroxylated analogs in Brown Bullhead (Ameiurus nebulosus) plasma from Lake Ontario

► PBDEs, MeO-PBDEs and OH-PBDEs were detected in Brown Bullhead from three locations in Lake Ontario. ► Concentrations of OH-PBDEs in plasma were about 50 folds higher than the MeO-PBDEs. ► OH- and MeO-PBDEs were evaluated against 20 authentic standards; eight OH-PBDEs and five MeO-PBDEs were identified. ► Additional seven unidentified OH-PBDEs and three unidentified MeO-PBDEs were detected in fish plasma. Polybrominated diphenyl ethers (PBDEs), methoxylated PBDEs (MeO-PBDEs) and hydroxylated PBDEs (OH-PBDEs) were detected and quantified in Brown Bullhead (Ameiurus nebulosus) from Lake Ontario. Samples were collected in 2006 from three different locations near the city of Toronto: Frenchman’s Bay, Toronto Island, and Tommy Thompson Park. A total of 117 plasma samples were pooled into 19 samples, separating males and females by site of capture. Pooled samples were analyzed for 36 PBDEs, 20 MeO-PBDEs and 20 OH-PBDEs, but only six PBDEs, five MeO- and eight OH-compounds were confirmed against standards currently available. These peaks were quantified as “identified” peaks, while peaks matching ion ratios but not matching the retention time of the available standards were quantified as “unidentified” peaks. Both “identified” and “unidentified” concentrations were combined to obtain a total concentration. No significant variations were obtained for total PBDE concentrations, ranging from 3.33 to 9.02ngg−1wet weight. However, OH- and MeO-PBDE totals ranged over 1 order of magnitude among the samples (not detected – 3.57ngg−1wet weight for OH-PBDEs and not detected −0.10ng/gwet weight for MeO-PBDE). The results of this study suggested that these compounds are ubiquitous in biota. Source estimation of MeO- and OH-PBDEs in freshwater fish were discussed. Considering that up to date no freshwater sources for MeO- or OH-PBDEs have been reported, concentrations found should be mainly related to bioaccumulation from anthropogenic sources, although other sources could not be dismissed.