'Dirty dozen' poisons hit Canada hardest

Talks aim to eliminate world's most toxic chemicals that have scarred the Arctic food chain.

Martin Mittelstaedt

Monday, March 20, 2000

Global talks sponsored by the United Nations to eliminate 12 of the most dangerous man-made pollutants, known as the "dirty dozen," reach a critical stage this week.

Negotiators in Bonn are trying to develop an international agreement to eliminate the use or creation of the chemicals, which include DDT, PCBs, and dioxins.

These 12 persistant organic pollutants (POPs) are some of the most feared pollutants in the world because they are linked to cancer, immune disorders, falling sperm counts, declines in wildlife populations, and the disruption of hormonal systems. The toxic compounds have a habit of lingering in living things and are now found in the tissues of virtually every creature on Earth.

The pesticides on the list are DDT, aldrin, chlordane, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex and toxaphene. Dioxins and furan are chemicals inadvertently produced as byproducts of incineration. PCBs, which have been used as heat-exchange fluids in electrical transformers and capacitors, round out the list.

A global agreement to phase out the chemicals would not only be a major public-health advance, but also a dramatic breakthrough in environmental protection.

The 120 countries taking part in this week's talks are divided between rich nations and developing countries, where some of the chemicals are used for pest control. Those countries would require funding to destroy existing stockpiles of the contaminants and develop alternatives, another divisive topic at the talks.

The negotiations began two years ago in Canada, but the Bonn session is expected to lead to a deal.

"We hope to come out with a final draft text of a convention" at the talks, said Steve Hart, Environment Canada's director of transboundary air pollution section, and co-chairman of the Canadian delegation. "To a large extent, most if not all of the substantive work needs to be done in Bonn."

Canada has a major stake in the successful outcome of the talks because it is one of the top global recipients of the chemicals.

Even though the pollutants have been banned or severely restricted in Canada and most developed nations, they are still used in many Third World countries where they evaporate into air currents, eventually to be dumped as precipitation in northern latitudes.

"The main concern is that these substances tend to use the Arctic as a sink," said John Crump, executive director of the Ottawa-based Canadian Arctic Resources Committee, an independent environmental group.

Consequently, Canadian Inuit and many top predators in the Arctic food chain have some of the highest recorded levels of these contaminants in the world, even though they are thousands of kilometres from the sources of the chemicals. Inuit adults have PCB concentrations in their blood that is seven times higher than other North American adults, according to the Canadian Arctic Resources Committee.

Mr. Hart said the talks are particularly important for Canada because of the threat the pollutants pose to the health of northern residents and wildlife. However, he said the plight of the Inuit in a wealthy country like Canada is not a major concern in many impoverished developing countries.

He said the Canadian delegation hopes to convince developing countries that eliminating the harmful chemicals will yield public-health and environmental benefits for their own populations as well.

Part of the difficulty in negotiating the treaty is highlighted by DDT, an insecticide that causes the thinning of egg shells from birds that may have consumed bugs exposed to the poison. The chemical compound wiped out vast numbers of birds in North America in the 1960s before it was banned.

But in the Third World, DDT has been effective in killing mosquitoes carrying the virus that causes the often-deadly malaria.

"It's a complex issue because on the one hand DDT is credited with saving many thousands of lives around the world, but on the other hand we all know the negative effects," Mr. Hart said.

It is expected that if a draft convention is produced this week, the fourth round of talks held to date, it will be ready for ratification by May, 2001.


The presence of persistent organic pollutants (POPs) in life across Canada.
- Humans, Baffin Island
The discovery of POPs in food, human blood samples and milk in the mid-1980s was a catalyst for action on POPs in Canada.
- Polar bears, Arctic and Hudson Bay
This species has some of the highest levels of POPs ever detected in wildlife. Highly contaminated cubs are less fit.
- Bald eagles, Great Lakes
POPs caused the near-extinction of fish-eating birds in this area in the 1970s. While bans have lowered POP levels, some species are still struggling to recover.
- Killer whales, West coast
Have some of the highest levels of POPs ever detected in marine mammals.
- Harbour seals, British Columbia
Have elevated levels of some POPs and are a food source of killer whales.
- Beluga whales, St. Lawrence River
Highly endangered, they live downstream from the industrial and agricultural pollution of the Great Lakes. The remaining 500-700 belugas are extremely contaminated with POPs.
- Harbour porpoises, Northwest Atlantic
High levels of POPs may be a contributing factor to the dwindling population of what is already considered a threatened species.
- Lake trout, Great Lakes
Predatory fish tend to have the highest levels of POPs. Consumption advisories and guidelines have been drawn up for Ontario and Quebec.
- Lobsters, P.E.I.
These have elevated levels of dioxins and furans (toxic byproducts of industry).

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