Chemical threat to killer whales

Over 50 percent of killer whales are at risk of extinction from toxic chemicals banned decades ago but which are still leaching into the seas


Polychlorinated biphenyls (PCBs): Banned in 1970s due toxic effect on humans and animals but still in use in paints, electrical equipment and construction until 1980s

Killer whale (Orcinus orca)
Weight: Up to 10 tonnes
Lifespan: 30-90 years
Length: Up to 10m

Biomagnification: PCBs, washed into rivers from unsealed storage sites, contaminate
seabed, building up in food chain and consumed by whales

Researchers have measured values as high as 1,300mg/kg in some killer whales

Phytoplankton
Zooplankton
Planktivores
Piscivores
PCBs accumulate in blubber

PCB levels as low as 50mg per kilo in blubber can cause infertility and severely impact
immune system


HIGH PCB RISK – Populations that may collapse within 30-50 years

Hawaii 101
Northeast Pacific Bigg’s Population size: 521
Brazil Unknown
Greenland Pop. unknown
Canary Islands Unknown
Strait of Gibraltar 36
UK 9
Japan Unknown

Habitat range


Sources: Science, Aarhus University, NOAA Fisheries 
© GRAPHIC NEWS