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Published in Spring 2003
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North America eliminates use of chlordane
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By John Moody
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Five years of teamwork between Canada, Mexico and the United States has ended the production and use of chlordane in North America.
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©Eric St-Pierre
Chlordane is a persistent organic pollutant that has often been used as a pesticide
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A pesticide, chlordane is used mainly in the extermination of termites. It is a pollutant that can take up to 20 years to degrade once it is released into the environment and a probable carcinogen that can damage the nervous system and liver.
Officials from the Environmental Protection Agency in the US and Mexico’s National Institute of Ecology collaborated with the CEC on the project.
“This experience will reinforce our expertise to eliminate other life-threatening toxins from our environment like lead and lindane,’’ said José Carlos Tenorio, program manager for the Sound Management of Chemicals (SMOC) at the CEC. “It is an example to the world of regional cooperation.”
In 1995, representatives from the three North American Free Trade Agreement (NAFTA) countries met in Oaxaca, Mexico, to “give priority to the management and control of substances of mutual concern that are persistent and toxic,” according to the final resolution. The SMOC program came into being as a result—its work on chlordane confirmed by the adoption of the Stockholm Convention on Persistent Organic Pollutants in 2001.
In all three countries, chlordane was used as a pesticide on crops, lawns and even furniture beginning in the 1950s, but by the mid-1970s severe restrictions were in place on its use and most applications were banned in the 1980s. By 1995 its use was phased out by both Canada and the US.
Production, however, continued until the last US producer voluntarily agreed to stop making chlordane under pressure from the government that it could hardly expect others to stop using it while allowing its continued production. Between 1992 and 1996, Mexico imported 212.8 tones of chlordane—all of it from the US.
After ending production, the next step was to find out how much Mexico was using and where.
Canadian and US agencies came to Mexico to show the best and cheapest ways to test for chlordane and monitor its use. They shared in detail how they had eradicated the use and which regulations were effective. The CEC also set up workshops to explain the dangers of the substance and offer alternatives. For example, heating furniture above certain temperatures kills termites just as effectively as spraying it with a noxious chemical.
Another factor in the success of the program was that it provided optimism for similar low cost efforts in the future. Apart from a few grants to Mexico for some studies, the bulk of the work was exchanging expertise and techniques, so it didn’t get lost in budget reviews or depend on political will.
“It was just sharing. The cooperation is working,’’ said Rocio Alatorre, the biologist who prepared the report on chlordane use in Mexico and who now works for the Mexico City environmental prosecutor’s office.
The only way to make sure chlordane isn’t still being used is
to continue monitoring levels in animals. If the levels fall,
then progress is likely being made; if they rise or stay the same,
it means a black market is developing.
What also made this easier was the fact that Mexico had begun to control the use of chlordane and by 1997 it was limited to urban use for controlling termites, mainly in houses. But ending its use completely took a number of years more and mutual help across the continent. It hasn’t been until now the authorities have felt confident enough to say publicly that the country had eradicated chlordane use completely.
On its own initiative, Mexico also took several steps with wider implications, showing that the government was becoming more environmentally conscious. One of the first was to ban the importation of chemicals that were prohibited in the producing country. In this, Mexico recognized the need to stop companies from turning to export markets when their products
were deemed dangerous at home.
For the first time, studies were also carried out on the use of chlordane in Mexico, as well as its effects on birds, fishes and worms. Though lower down the food chain, when these animals become contaminated, the pollutant quickly makes its way to humans.
So the SMOC program helped Mexico to look hard where it hadn’t focused before and by 1998 it had banned the use of chlordane. The next four years were taken up with identifying where the chemical was still being used and working to stop it, including monitoring distributors and suspected buyers.
The key now will be to follow up. The only way
to make sure chlordane isn’t still being used is to continue monitoring levels in animals. If the levels fall, then progress is likely being made; if they rise or stay the same, it means a black market is developing. Countries in Africa
and China still produce chlordane and it is possible that its cheap cost and ease of use will tempt some people to buy it. So far, though, there are no signs of this happening, although there are rumors.
“We need resources to do things like measure levels of chlordane in fish—first now and then again in a few years—to make sure the levels are falling,” said José Castro, an official at Mexico’s National Institute of Ecology, the agency charged with protecting the Mexican environment. The pressure of NAFTA cooperation should be enough to get the Mexican government to loosen the purse strings.
And, as it takes up to 20 years to degrade, it will be around for a while yet, so the war isn’t won.
“Chlordane hasn’t disappeared. We can be sure
the detectable levels will go down, but we can’t and shouldn’t forget about it,” said Tenorio.
The benefits of the CEC’s work in Mexico haven’t just been chlordane-related. Other substances have been looked at. As a result of the Oaxaca agreement, for example, Mexico measured mercury levels for the first time ever. Thanks to centuries of silver mining, there is a long history of mercury use, as it is used to get the metal out of the ore.
“If we hadn’t started working with the Commission, we wouldn’t realize how big a problem mercury is.
It is a national health problem and we didn’t know it,” said the INE’s Castro.
Heartened by these results, officials are now turning their attention to other chemicals, principally lindane and lead.
“This is the precedent to follow to eradicate more substances,” said the INE’s Castro.
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