N. Residents26 samples; S. Resident 6 samples; Transients15 samples; Dungeness Spit Transient1 sample
To serve as a comparative base, note that the action level for all fish products in Canada is 2 ppm

It cannot only be local sources of PCBs that impact the survivability of the killer whale populations of the northeastern Pacific.

While the western world struggles with the inheritance of PCB use, production ceased and disposal has been regulated since the late 1970's whereby levels of this toxin should be decreasing. Tragically, in other parts of the world, there are still PCBs in use, there is inadequate control of PCB disposal and, PCBs may even still be produced. The equal distribution of PCBs in the seawater of the northern and southern hemisphere indicates that PCB use in Asia expanded when use in the industrialized countries ceased.

Asian sources of PCBs are believed to significantly contribute to the plight of the killer whales. High temperatures and heavy rainfall in tropical Asia are thought to contribute to increasing the speed of dissipation of PCBs into the atmosphere. Studies indeed indicate that the residence time of POPs in tropical waters is shorter, favourable for the Asian aquatic environment but not for the global environment. Recent research has indicated that it takes only 5 to 10 days for PCBs to reach British Columbian waters from Asia.

It is estimated that only very little of the global "budget" of PCBs has entered the ocean. Without dire changes in global approach to PCB use and disposal, it is not anticipated that the levels in marine mammals will decrease.

The iconic killer whales of the northeastern Pacific have been found to have the highest PCB loads of any marine mammal researched (Oceana). This reality is cause for great alarm. However, this reality coupled with killer whales being a species with such emotional appeal and global exposure, also allows for very powerful educational opportunities.

The contrast in the PCB loads of the northern and southern resident killer whale populations is of huge relevance in providing a case study in what the increased concentration of PCBs can have on the survivability of a species.

The reality of gender differences in bioaccumulation indicates the direct threat to male survivability and the impact of the generational effect.

The case of the transient killer whales indicates the significance of trophic level in bioaccumulation.

Collectively, the killer whales of the northeastern Pacific are providing an alarming testimony to the global issue of PCBs. Research is ongoing in determining the extent of the impact of global sources of PCBs (aerial, water and biological transport sources) but we must act now, embracing the precautionary principal - for the good of the whales, for the good of global ecosystems and for our own good since we occupy the same trophic level as the killer whales do.

With killer whales being apex predators, they indeed serve as indicators of the state of the marine ecosystem and the reality of the effects of bioaccumulation. Time for us all to take note and responsibility - for they live in the oceans we share.