Flawed tests hide pesticide danger
Flawed federal safety tests understate the true dangers of pesticides (POISONS) and other hazardous chemicals in Canada's environment, unpublished Health Canada research reveals.
Subject: Flawed tests hide pesticide danger..................synergistic effects,etc............
Date: Sun, 30 Sep 2001 14:15:04 -0400
From: Stephen Tvedten <steve@getipm.com>
Organization: Get Set Inc. (www.getipm.com)
To: Paul Helliker <phelliker@cdpr.ca.gov>
Director, State of
California, Department of Pesticide Regulation
cc: Christine Whitman whitman.christine@epa.gov
Dear Mr. Helliker, I thougtht you might like to read a Sunday, September 30, 2001 article entitled: Flawed tests hide pesticide danger from The Ottawa Citizen by Tom Spears.
Flawed federal safety tests understate the true dangers of pesticides (POISONS) and other hazardous chemicals in Canada's environment, unpublished Health Canada research reveals.
Mixing pesticides and industrial pollutants makes them more toxic together than any of the chemicals on its own, the research shows. Such a mixture -- from traces of old DDT to modern bug sprays and weed killers -- is what all Canadians carry in our bodies from environmental exposure.
Yet federal scientists who evaluate each pesticide used in Canada only examine these hazards one chemical (active ingredient) at a time.
And Health Canada scientists are now warning that the whole testing system for new pesticides may be too flawed to show their true dangers.
They have presented their results at two conferences on toxic chemicals this year. For example, the scientists were surprised to find that when they exposed pregnant rats to chemical mixes -- including pesticides -- 80 per cent of the babies were born dead.
This rate was "unexpectedly high," the study found, since each chemical in the mixture was given in doses that were supposed to be non-lethal.
Even the surviving babies didn't escape serious harm. The young rats showed abnormal behaviour after their mothers were exposed to a mix of chemicals chosen to match the contaminants commonly found in humans.
It's still uncertain whether the damage was done in the womb or when babies drank their mothers' contaminated milk. The relationship between the experiment and the dosages found in humans has not yet been examined.
Remarkably, Health Canada hasn't made public either these results or the doubts about its own testing methods, even though it has known about them all this year, and perhaps longer.
The belief that a chemical mix is worse than individual chemicals has circulated for years. The theory is many chemicals can build on each other's ability to do harm, a process called "synergistic effects." So Health Canada set up a team to study the synergistic effects of environmental chemical mixtures on the brains and nervous systems of rodents.
It examined a mix of pesticides and PCBs, a class of industrial oil banned in the 1970s that still persists in the environment. All the pesticides were older and no longer registered for use, a Health Canada spokesman said. But the conclusion remains: Testing pesticides individually is very different from examining them in a mix.
One of the researchers, Wayne Bowers, presented preliminary results at a seminar in January. He also travelled to Portugal in June to tell the International Neurotoxicology Association at its biennial meeting. The results haven't yet been "peer-reviewed," or examined by independent experts; nor have they been published in any journal.
Still, the results indicate Health Canada's risk assessment methods may be out of date and perhaps undependable. It's now a research priority within the department to learn more about ways in which chemical mixtures do more harm than single chemicals. But Health Canada's top policy officials are telling the public all their risk assessment studies and methods are thoroughly up-to-date. "The Pest Management Regulatory Agency continually adopts the most up-to-date health and environmental assessment methods," the department says in "media lines" prepared to give the minister bite-sized responses to possible questions.
Mixtures of pesticides are common. The U.S. Geological Survey recently sampled streams and groundwater near Lakes Erie and St. Clair, finding 30 pesticides. The mixtures ranged from two to 18 pesticides per sample, and stayed in the water four to six weeks after the pesticides were sprayed.
These results will be reported at a conference in Montreal next month. Quebec government scientists will tell the same conference they have found pesticides such as 2,4-D, dicamba, atrazine and metolachlor in more than half the samples from 20 rivers in the province. They often find 10 to 15 pesticides in one sample.
Scientists have known for years they have to add up all the chemicals in a lake to figure out the overall toxic levels, says David Schindler of the University of Alberta. But testing all the mixes will be far slower and more expensive than testing one at a time, he warned.
"Look at the garbage heap of things that we have in any ecosystem, and my God! What concentrations and mixtures do you include in these analyses?" he said. "I know they've been wrestling with this, and whatever they do will be really expensive."
On Tuesday, Canada's environment commissioner issues her annual report, and this year's focuses on the Great Lakes and St. Lawrence, which hold one-fifth of the world's fresh surface water. Two weeks later the International Joint Commission, the Canada-U.S. body overseeing the Great Lakes, meets in Montreal.
Talking Points
These are some of the latest 'media lines' Health Canada has written for its minister to recite if questioned in public on pesticides.
- The minister of Health plans to introduce a bill in the near future to replace the existing Pest Control Products Act with a new act.
- The new act will modernize the PCPA so it better meets the needs for assessing and managing the risks posed by pesticides in the 21st century.
- It will ensure Canada's children are given special protection from health risks posed by pesticides.
- Although the current PCPA is older legislation, it has not prevented the adoption of new scientific advances in the regulation of pesticides in Canada. The Pest Management Regulatory Agency continually adopts the most up-to-date health and environmental assessment methods.
- Pesticides registered in Canada undergo thorough scientific assessment by Health Canada's Pest Management Regulatory Agency and their availability, sale and use are subject to strict regulation through federal, provincial and territorial legislation.
Source url: http://www.canada.com/ottawa/ottawacitizen/story.asp?id={14784A1A-B9D6-4665-BE85-F9ADE9A98DE1}
Well Mr. Helliker, I am certainly glad I am not in your shoes, I would hate to know that the POISONS that I "registered" and demand can only be used to "control" pest problems have not been adequately tested, are harming innocent people and beneficials and are not even "controlling" the pest problems. When will it be 'legal' (in your opinion) to use safe and far more effective (unregistered) alternatives to actually control pest problems?
Respectfully, Stephen L. Tvedten
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