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A more complete picture of pesticides in rivers
The Ministère du Développement durable, de l'Environnement et des Parcs du Québec (MDDEP) now has a more complete picture of pesticide contamination in the tributaries of the St. Lawrence between Montreal and Lake Saint-Pierre. The information available until just recently covered only 20 rivers on the South Shore. But in November 2007, the Department published a new study of four tributaries on the North Shore.
The study, entitled Les pesticides dans quelques tributaires de la rive nord du Saint-Laurent: rivières L'Assomption, Bayonne, Maskinongé et du Loup, was conducted under the St. Lawrence Plan for Sustainable Development (SLP). The four rivers chosen for the study have drainage basins with large areas under agriculture: 42% for the Bayonne River, 12% for the Assomption River, 9% for the Du Loup River, which flows into Lake Saint-Pierre and 6% for the Maskinongé River, which also flows into Lake Saint-Pierre.
The research findings show that pesticides were found at the mouth of each of the four watercourses, most often in the Bayonne and Assomption rivers, which drain more farmland. In both of these rivers, the products detected on a regular basis were herbicides used for corn and soya crops, including atrazine, metolachlor and dicamba. From 7% to 8% of the samples taken in 2002 showed levels in excess of the water quality criteria for the protection of aquatic species.
In the remaining two rivers, the presence of herbicides was less frequent, but insecticides were detected at levels above the quality criteria in 13% of the samples taken in the Maskinongé River in 2004, and in 28% of the samples taken at the mouth of the Du Loup River in that same year. The insecticides present in the highest concentrations were mainly chlorpyrifos, dimethoate and malathion.
For information:
Isabelle Giroux
Ministère du Développement durable, de l'Environnement et des Parcs du Québec
Telephone: 418-521-3820, ext. 4720
E-mail: isabelle.giroux@mddep.gouv.qc.ca.
Date modified: 2008/06/19 – Important Notices
