| Abstrakt: |
Contaminants described as organochlorines (OCs; e.g., polychlorinated biphenyls [PCBs]) are present in tissues of marine mammals, including beluga whales (Delphinapterus leucas), but the complexity of contaminant exposure often is not fully known. The PCBs, OC pesticides, polybrominated diphenyl ether (PBDE) flame retardants, methylsulfonyl (MeSO2)- and hydroxy (OH)-PCB metabolites, and OH-PBDEs and methoxylated (MeO)-PBDEs were determined in the liver of beluga whales from two Canadian populations: the St. Lawrence Estuary (SLB; n 5 6), and western Hudson Bay in the Canadian Arctic (CAB; n 5 11). The ΣPCB, ΣDDT, and ΣPBDE concentrations were higher (p < 0.05) in SLB versus CAB. Of 18 detectable OH-PCBs in SLB (mainly 4-OH-CB107, 4-OH-CB112, and 4'-OH-CB120), only 4'-OH-CB120 was found in CAB. The ΣOH-PCB concentrations were less than 0.2% of the ΣPCBs in both populations but were higher (p < 0.05) in SLB (65 ± 22 ng/g lipid wt) than in CAB (3.1 ± 0.5 ng/g lipid wt). The ΣMeSO2-PCB concentrations were higher in SLB (3,801 ± 1,322 ng/g lipid wt) relative to CAB (77 ± 23 ng/g lipid wt) and were 11 and 4%, respectively, of the ΣPCB concentrations. Of the 15 OH-PBDEs, only two congeners were detectable, but not quantifiable (notably 2'-OH-BDE 68 and 6-OH-BDE 47), in animals from both populations. Of the 15 MeO-PBDEs, 4'-MeO-BDE 17 and 6-MeO-BDE 47 in the SLB (n = 2) and 2'-MeO-BDE 68 and 6-MeO-BDE 47 in the CAB (n = 2) had concentrations from 20 to 100 ng/g lipid weight. The OH-PBDEs and MeO-PBDEs most likely are of natural origin and accumulated in beluga whales, whereas the OH-PCBs and MeSO2-PCBs are metabolites derived from accumulated PCBs. Canadian beluga whale liver contains previously unidentified organohalogen contaminants and metabolites and, thus, a complexity of contaminant exposure that may be impacting the health of Canadian beluga whale populations. [ABSTRACT FROM AUTHOR] |
Plný text