Organohalogen contaminants and metabolites in beluga whale (Delphinapterus leucas) liver from two Canadian populations

Abstract

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=6), and western Hudson Bay in the Canadian Arctic (CAB; n=11). The sigmaPCB, sigmaDDT, and sigmaPBDE 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 sigmaOH-PCB concentrations were less than 0.2% of the sigmaPCBs 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 sigmaMeSO2-PCB concentrations were higher in SLB (3801 +/- 1322 ng/g lipid wt) relative to CAB (77 +/- 23 ng/g lipid wt) and were 11 and 4%, respectively, of the sigmaPCB 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.

Concentrations of chlorinated and brominated contaminants and their metabolites in serum of harbour seals and harbour porpoises

“…Moreover, no HO-PBDEs were found in ringed seal blubber and beluga whale blood and liver (Kelly et al, 2008). In contrast, detectable but not quantifiable HO-PBDE concentrations were reported in beluga whale livers (McKinney et al, 2006b) and very low yet measurable concentrations of 0.01 to 0.1 ng/g lipid equivalent were found in blubber and milk of beluga whales (Kelly et al, 2008). However, since concentrations of PBDEs in harbour seals are lower than levels in harbour porpoises, a greater capacity for debromination of PBDEs in harbour seals is assumed as previously shown for BDE 209 in grey seals (Thomas et al, 2005).…”

Organohalogen contaminants and metabolites in cerebrospinal fluid and cerebellum gray matter in short-beaked common dolphins and Atlantic white-sided dolphins from the western North Atlantic

“…The extraction and clean up of CSF and cerebellum gray matter for OC, PCB, PBDE, MeSO 2 -and OH-PCB, 4-OH-heptachlorstyrene (4-OH-HpCS), and OH-PBDE compounds were based on methods described in detail elsewhere for blood, liver, and brain with some modifications (Chu et al, 2003;Gebbink et al, 2008a,b;McKinney et al, 2006;Muir et al, 2006;Sandala et al, 2004 (and references therein)). Other BFRs including pentabromotoluene (PBT), hexabromobenzene (HBB), 2,2',4,4',5-pentabromobiphenyl (BB-101) and total-(α)-hexabromocyclododecane (HBCD) were also measured according to recently published procedures (Gauthier et al, 2008).…”

“…These OHCs include such legacy chemicals as the organochlorine pesticides (OCs) including dichlorodiphenylethanes (i.e., DDTs), dieldrin, chlordanes, and hexachlorocyclohexanes (HCHs), polychlorinated dibenzo-p-dioxins, dibenzofurans, and polychlorinated biphenyls (PCBs); and emerging compounds such as polybrominated diphenyl ethers (PBDEs) (Fair et al, 2007;Johnson-Restrepo et al, 2005;McKinney et al, 2006;Tuerk et al, 2005) and hexabromocyclododecane (HBCD) (Johnson-Restrepo et al, 2008).…”

“…OH-PCBs have been reported in the liver of beluga whales (Delphinapterus leucas) (McKinney et al, 2006) and in the plasma of bottlenose dolphins (Tursiops truncatus) (Houde et al, 2006). OH-PBDEs have also been found in beluga whale liver (McKinney et al, 2006) and in the blood of Pacific killer whales (Orcinus orca) (Bennett et al, 2009). …”

Volumetric Neuroimaging of the Atlantic White‐Sided Dolphin (Lagenorhynchus acutus) Brain from in situ Magnetic Resonance Images

“…These include anthropogenic chemicals such as hydroxylated polychlorinated biphenyls (OH-PCBs; Sandala et al, 2004;Houde et al, 2006;McKinney et al, 2006) and polybrominated diphenyl ethers (PBDEs; De Boer et al, 1998), as well as biotoxins from harmful algal blooms (Scholin et al, 2000). These chemicals can target the brain (Viberg et al, 2003;Kimura-Kuroda et al, 2005;Silvagni et al, 2005).…”