VANCOUVER - Toxic chemicals in killer whales and other marine wildlife are a crucial area of scientific study because they provide an important signal about the types of chemicals humans may be exposed to, says a marine scientist.
Peter Ross, a toxicology research scientist at the Institute of Ocean Sciences in Sidney, B.C., has studied the majestic creatures and other wildlife to determine the level of chemicals in their bodies - and the eventual exposure to humans.
"The killer whales are telling us that we have a pollution problem on a global scale," said Ross, who published a scientific paper called Fireproof Killer Whales.
That's primarily because the study, in part, examined the effects of polybrominated didphenyl ethers, a fire retardant chemical (PBDEs) found high up in the food chain.
"Killer whales can give us an amplified signal of the kinds of chemicals that humans might be exposed to," he said. "They can give us an early warning sign."
The problem, Ross has found, is global and comes from two sources: regional, from Canada and the U.S.; and global, from air pollution that emanates in Asia and drifts across to North America.
"We can paint a picture whereby global pollutants are the concern for a long-lived whale at the top of the food chain."
It's also a concern for humans.
"Since we as humans share food webs with killer whales and harbour seals, if the killer whales and seals are telling us something about contamination of those food webs then we as humans can hopefully learn from that," Ross said.
There has been progress in reducing toxic chemicals, said Ross, citing the 2001 Stockholm Convention on "persistent organic pollutants that banned 12 pollutants including polychlorinated biphenyls (PCBs), DDT, dioxins and others.
Despite the ban, they still turn up in killer whales and other marine mammals, Ross said, adding killer whales won't be free of PCBs in their bodies until the 22nd century.
"Essentially, persistent chemicals, whether PCBs, DDT, dioxins or PBDEs, will amplify in aquatic food webs and end up at high levels at the top of the food chain."
And PBDEs, used in fire retardant chemicals, are a concern because they have been doubling in the environment every 3 1/2 years in fish and harbour seals, said Ross.
"That is troubling because the lesson we learned from PCBs is that they do not go away quickly."
PBDES are used in electronics, automobiles, textiles and many other consumer products.
They give off a gas or deteriorate over time and eventually end up in streams, rivers and the ocean.
Ross cites several reasons why humans should care about pollutants in killer whales and other marine mammals.
Besides having a legal obligation under the Species At Risk Act, he said by acquiring more knowledge, humans can work to reduce or eliminate those chemicals that end up being a problem in killer whales and other wildlife.
Ross remains optimistic that PBDEs and other chemicals can be checked as PCBS were.
"We have seen PCB levels drop by three-fold in killer whales since 1970," he said
Source: The Canadian Press
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