Predicting global killer whale population collapse from PCB pollution

Killer whales (Orcinus orca) are among the most highly polychlorinated biphenyl (PCB)–contaminated mammals in the world, raising concern about the health consequences of current PCB exposures.  PCB-mediated effects on reproduction and immune function threaten the long-term viability of >50% of the world’s killer whale populations. Despite a near-global ban of PCBs more than 30 years ago, the world’s killer whales illustrate the troubling persistence of this chemical class.

http://science.sciencemag.org/content/361/6409/1373