Whales Threatened by Toxic Chemicals
Fire retardant chemicals are accumulating in British Columbia's killer whales at concentrations high enough to likely harm their health.
Among many pollutants found in orca blubber, of most concern are the now-banned, yet still persistent, polychlorinated biphenyls (PCBs), and their current replacement, polybrominated diphenyl ethers (PBDEs), used for adding fire resistance to many household products.
Toxins have been accumulating over several decades in resident whales. The salmon they consume pick up contaminants at sea. Southern Strait of Georgia resident whales also feed on local fish which contain higher chemical concentrations than salmon. Thus waste from both the lower mainland and eastern Asia contribute to toxicity in southern whales.
Compared with northern resident orcas, southern whales have three times higher PCB levels and five times more PBDEs. Even higher contaminant concentrations exist in the blubber of transient whales, which feed further up the food chain on marine mammals.
For the southern resident whales, listed as endangered under the federal Species at Risk Act, toxic chemical interference with endocrine functioning is one factor identified as jeopardizing their survival.
Peter S. Ross. 2006. Fireproof killer whales (Orcinus orca): flame-retardant chemicals and the conservation imperative in the charismatic icon of British Columbia, Canada. Canadian Journal of Fisheries and Aquatic Sciences. 63(1): 224-234.