Pesticide and herbicide horror stories have become part of 20th-century lore, and rightly so. The liberal use of toxins to kill anything that squeaks, buzzes, or grows wild took off in the last century. Unsurprisingly, the origin of this trend lies in the development of chemical weapons.
Thankfully, we’ve come a long way since the days of Agent Orange and DDT, yet pesticide and herbicide residue still seems to linger everywhere, from our food to our golf courses to our lawns. How concerned should we be?
Lisa Gue, environmental health policy analyst for the David Suzuki Foundation in Ottawa, cautions us to stay vigilant. “It really is intuitively obvious that pesticides are designed to kill,” she says.
The acute effects of pesticides on human health are well known. A 2007 report published by the David Suzuiki Foundation found that over 6,000 Canadians are poisoned by pesticides each year. Disturbingly, 46 percent of these poisonings involved children under the age of six.
There’s no doubt that accidental high doses of pesticides can be lethal, but what about the chronic, long-term effects of pesticide exposure? “Study after study has linked pesticide exposure to some fairly serious health effects, including cancer, reproductive problems, and neurological diseases,” says Gue.
One such study, a pesticide literature review published by the Ontario College of Family Physicians, found that pesticide-related health effects included “nine types of solid tumours, non-Hodgkin’s lymphoma, leukemia, genotoxic effects, and skin diseases.”
However, while these studies are compelling, they lack the requisite randomized, controlled trials that would make them conclusive. According to the literature review, “most of the studies done examine occupational groups with higher exposures to pesticides than those of the general population.”
Stelvio Bandiera, professor of biomolecular and pharmaceutical chemistry at UBC, studied the effects of the pesticide methoxychlor and its relationship to breast cancer. Bandiera found that this pesticide did not cause cancer but did exacerbate it slightly in rodents that already had cancer.
He believes that pesticides pose a minimal risk to humans because the levels in the environment are so low. Furthermore, in Canada, herbicides are far more ubiquitous than pesticides.
Herbicides do contain toxic chemicals but are designed to kill plant life. According to Bandiera, “herbicides break down fairly quickly once they are applied to crops. And they affect plant growth mechanisms that are not even close to those found in humans.”
Bandiera assures us that toxicity levels in the environment “generally fall below the recommended Health Canada guidelines, and the guidelines are designed with a safety margin.”
Are we protected?
In 2006 Canada’s new Pest Control Products Act came into force. This act regulates the registration of pesticides and requires rigorous testing, including lifelong toxicology studies, carcinogenicity, proof of absence of birth defects, cumulative effects, and environmental effects.
While this act does provide stronger protection, Lisa Gue believes more can be done. “We have urged the federal government to stop registering for use in Canada pesticide products that have only aesthetic applications,” says Gue. “This would ensure a consistent level of protection across the country.”
The cosmetic use of herbicides is a controversial subject in Canada. At the provincial level, only Ontario and Quebec have introduced restrictions preventing the sale of herbicides for cosmetic purposes. At the municipal level some cities have banned the use of pesticides outright, while others have opted for the softer Integrated Pest Management (IPM) approach, which emphasizes pesticides and herbicides as a last resort only.
“The problem is that when you allow pesticide use on lawns and gardens, it tends not to be audited at all, and it can be a way to extend the use of pesticides,” says Gue. “Experience has shown that cities that have opted for IPM have been less effective in reducing pesticide use.”
Who protects wildlife?
While the debate over the human health effects of pesticides and herbicides waxes on, there is one fact we cannot deny: our chemical warfare with nature has very real casualties.
“Wildlife are susceptible to different classes of pesticides and the worry is that the runoff from golf courses and parks will find its way into streams and lakes,” says Bandiera. “There have been well-documented cases where there have been serious die-offs of fish, birds, and insects from exposure.”
Both Bandiera and Gue agree that the domestic use of pesticides and herbicides is unwarranted. “Pesticides on our lawns deliver such negligible value that the risks cannot be justified,” says Gue. This much is clear—we need to call a truce on our lawn warfare.
Chemicals in lawn pesticides
Insecticides to avoid
- Dichlorvos (DDVP)
Herbicides to avoid
- Disodium methanearsonate (DSMA)