High PCB Concentrations in Free-Ranging Pacific Killer Whales, Orcinus orca: Effects of Age, Sex and Dietary Preference

Killer Whales (Orcinus orca) Face Protracted Health Risks Associated with Lifetime Exposure to PCBs

“…We also used the model to evaluate killer whale contamination response to future exposure scenarios ranging from no change to gradual declines based on environmental half-lives between 20 and 30 years. Similar simulations were conducted for the southern resident population using the SR diet history from Figure 2 (and others) but can only be compared to PCB data from 6 animals (4 males, 2 female; ∼7% of the population) collected in 1994 (6). A final simulation ran the PB model to steady state using a fixed diet PCB concentration consistent with the Canadian tissue residue guideline (TRG) for the protection of fish-eating wildlife (33).…”

“…After considering influential factors such as age, sex, dietary preferences, and calving order on observed contaminant concentrations, a weight of evidence suggests that the risk of adverse health effects is high (6,7), although direct evidence in killer whales is, understandably, lacking. However, significant unknowns remain for killer whales, with one-time biopsies providing a restricted temporal "snapshot" of contaminant concentrations stored in blubber, no samples or data from before 1993, and no direct means of assessing the contribution of exposure history to present burdens.…”

A Model Approach for Estimating Colony Size, Trends, and Habitat Associations of Burrow-Nesting Seabirds

“…As reviewed in Chapter 2a, mammalian apex predators such as killer whales (Orcinus orca) and harbor seals (Phoca vitulina) have exhibited body burdens of persistent toxics (PCBs and PBDEs) expected to cause serious health effects (Ross 2006). Ross et al (2000) characterized the Southern Resident Killer Whale population as among the most contaminated cetaceans in the world. Exposure to PBTs have been implicated as a cause for population decline in this population, as well as an impediment to their recovery (Krahn et al 2002).…”

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

“…Odontocetes (toothed whales, dolphins, and porpoises) bioaccumulate extremely high levels of organohalogen contaminants (OHCs) in their blubber Kannan et al, 1993;Muir et al, 1996;Ross et al, 2000). 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).…”