Does the pesticide ban work?

Does the ban on cosmetic pesticides work?

Ontario’s ban came into effect on April 22, 2009. Since then, there has been a dramatic decline in the concentration of pesticides in urban watercourses – according to a study released by the Ministry of the Environment. In the summers of 2008 and 2009 (the year before and after the ban took effect), staff from the Ministry of Environment and five conservation authorities conducted a water quality monitoring study of  ten urban streams and creeks, and tested them for as many as 105 pesticides and breakdown products. Preliminary results show that in 2009, concentrations of the three most popular cosmetic pesticides dropped by more than 80 per cent: 2,4D reduced the most by 86 per cent followed by dicamba (82 per cent) and MCPP (2-methyl-4-chlorophenoxyacetic acid; 78 per cent).
Approximately 80 per cent of more than 300 retailers and lawn care companies are believed to be complying with the ban. An enforcement program is rolling out to deal with the remaining 20 per cent.


  1. windmill

    So my question is, in which month was monitoring done? In May after most of weeds have been treated? No, that can't be because April 22nds treatments would still register. Maybe one in May (2008) and one in August? Long after spring weed control has been washed away? How can results be best skewed for the greatest dramatic effect?

  2. Jim Liebold

    Interesting point. You have to wonder what the side effects of the ban will be. Higher use / concentrations of fertilizer residues in the water system – not a good scenario


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