A recent Quebec study has uncovered the presence of dozens of pesticides in tap water—even after treatment at a water facility—raising concerns about long-term exposure risks. The study, led by Université de Montréal’s environmental chemistry professor Sébastien Sauvé, was published in the June issue of Water Research.
Between 2021 and 2023, researchers collected bi-weekly samples from the Châteauguay River, which passes through agriculturally intensive regions. Samples were taken as water entered and exited a treatment plant supplying local tap water.
The study found that although none of the samples exceeded Quebec’s safety guidelines, traces of at least 50 different pesticides and their metabolites remained after treatment. In some instances, these chemicals were more concentrated in the treated water than in the raw river water.
Among the most prevalent was glyphosate, a widely used herbicide and the active ingredient in Roundup. Despite bans in several Quebec municipalities, including Montreal, glyphosate was consistently found. The World Health Organization has labeled it “probably carcinogenic,” though Health Canada maintains it’s safe when used correctly.
Researchers emphasized concerns over the “cocktail effect”—the unknown combined impact of multiple pesticides in water. Sauvé warned that while individual concentrations may be low, their cumulative interaction could pose unknown risks.
Environmental health expert Maryse Bouchard echoed these concerns, calling the variety of molecules “disturbing.” Meanwhile, Sarah Dorner of Polytechnique Montréal highlighted that 80% of pesticide exposure comes from sources other than drinking water, such as food.
The study calls for stricter water quality regulations and suggests that European-style cumulative pesticide limits be implemented. While Quebec’s Environment Ministry said it monitors agricultural pesticide use annually, Sauvé noted that peak periods of contamination may not be captured.
Source: Swifteradio.com
