PCBs may threaten killer whale for decades

SIDNEY, British Columbia, Sept. 11 (UPI) -- A Canadian study suggests Orca whales, may continue to suffer the effects of polychlorinated biphenyl, or PCB, contamination for decades.

The study by Brendan Hickie, Peter Ross and colleagues at Canada's Institute of Ocean Sciences determined orcas, also known as killer whales, are the most PCB-contaminated creatures on Earth.

Scientists are now trying to discover how current declines in environmental PCBs might affect orcas throughout an exceptionally long life expectancy, which ranges up to 90 years for females and 50 years for males.

The researchers used mathematical models and measurements of PCBs in salmon -- orcas' favorite food -- and ocean floor cores to recreate a PCB exposure history to estimate PCB concentrations in killer whales. It concluded the threatened northern population of 230 animals will likely face health risks until at least 2030, while the endangered southern population of 85 orcas might face such risks until at least 2063.

PCBs make whales more vulnerable to infectious disease, impair reproduction, and impede normal growth and development, the researchers said.

The report is to be detailed in the Sept. 15 issue of the journal Environmental Science & Technology.