Concern raised in B.C., Washington state

Larry Pynn

Vancouver Sun

Wednesday, March 14, 2007

Levels of a toxic flame retardant are growing so quickly in coastal marine waters they are expected to surpass PCBs as the leading contaminant in endangered southern resident killer whales, a federal scientist warned Tuesday.

Peter Ross of the Institute of Ocean Sciences in Sidney near Victoria said in an interview that research shows levels of PBDEs (polybrominated diphenyl ethers) are steadily increasing in harbour seals in southern Puget Sound in Washington state, with levels in seals in B.C.'s Strait of Georgia expected to be similar.

At the current rate of increase, PBDE levels are predicted to exceed those of PCBs (polychlorinated biphenyls) in killer whales in our shared waters by 2020.

That will further confound recovery efforts, Ross said.

PBDEs are the latest emerging threat to a population of killer whales that is already among the most polluted marine mammals in the world and is officially endangered in Canada and the U.S.

Two toxic lighter forms of PBDEs, penta and octa, were voluntarily withdrawn from the Canadian and U.S. marketplaces more than two years ago, Ross said. Environment Canada is re-evaluating a third type, deca, in light of research showing it can break down and resemble the two other forms and "magnify" up the food chain.

"Washington state is also trying to get rid of all three forms," Ross added.

Unlike PCBs, which were used largely as coolants in industrial transformers before being banned 30 years ago, PBDEs are widely used as flame retardants in polymer resins and plastics and found in consumer products such as furniture, TVs, stereos, computers, carpets, and curtains.

PBDEs find their way into the marine environment through the air or through runoff and effluent, and are thought to pose a risk to the endocrine system, reproductive health, the immune system, and development.

Ross said scientists are often asked to prove the threat posed by a chemical before it is removed, but he argued that in this case the "cautionary principle" should apply, given the killer whales' precarious existence.

"Any way you cut that picture, these chemicals are a perplexing conservation threat."

PBDE levels in harbour seals in Puget Sound have increased steadily: 14 parts per billion in 1984, 281 ppb in 1990, 328 ppb in 1993, 644 ppb in 1996, and 1,057 ppb in 2003.

In comparison, PCBs levels have declined: 100,000 ppb in 1972 and 17,000 ppb by 1984.

Killer whales carry 10 times the contaminants of harbour seals, which means an increase in PBDEs in seals is immediately cause for concern. "They might be much more vulnerable to these impacts," Ross said.

He suggested that society use alternative fire retardants that do not threaten both marine life and first nations who are heavy consumers of marine life. "There is sufficient scientific evidence to raise concerns about all three forms of PBDEs. We should be very careful about use of any of these products."
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