Insecticide Inquiry from Twitter

April 27, 2009

in 2007-2010 Term,Environment

Had an inquiry come in via Twitter from @ecoDomestica and @ChrisInEdmonton asking the following:

Why is Dursban, an insecticide that kills frogs & tadpoles, being used as part of #yeg mosquito control program?

I inquired with the city’s Office of the Environment and received the following information:

There is no evidence that the amounts of Dursban used, and the targeted nature of the City of Edmonton’s program has had any effect on amphibian populations.

While laboratory trials with large doses of directly injected organophosphates have shown effects on developing amphibians, this does not match the kinds of exposures amphibians receive in field conditions.

Both wood frogs (Rana sylvatica) and boreal chorus frogs (Pseudacris maculata) remain abundant in all suitable habitats in the Edmonton area. The City continually monitors populations of non-target organisms and has not seen any decline in amphibian populations. All native species of frogs are thriving in habitats treated by the control program.

As with fluoride, all things in moderation I suppose.

Tagged as: Environment, twitter

{ 2 comments… read them below or add one }

Vivian April 27, 2009 at 9:50 pm

My concern is that it is bad enough to be banned by the Federal Government, and the ban was only lifted to deal with mosquitos who may carry West Nile- which these mosquitos do not.

My major concern is sadly not for frogs- but for my children. While they may not play near the spraying areas, they are living in a city that chooses a short cut and is taking advantage of the federal lift on the ban to take care of nuisance mosquitos rather than the dangerous ones the ban was lifted for.

I am angry about this because this is the exact type of thing that makes people feel apathetic about democracy. Obviously there is something wrong with Dursban if it was banned in the first place, but now Edmonton has just “decided” it’s FINE! Don’t WORRY about it! Just pretend we’re all okay!

My children will be just as disgruntled as I am about the government, and that makes me angry.

don April 29, 2009 at 12:30 pm

Thanks to Mike Jenkins with the city’s Office of Environment for the following further detail quoted below:

Dursban was never banned. In 2000, following a re-evaluation of the various uses of chlorpyrifos (the active ingredient in Dursban), the manufacturer voluntarily withdrew the use of Dursban from domestic and structural uses. The Federal government supports our use of Dursban, and in fact our policy places more restrictions on its use than the Federal label requires.

The label has always included use of the product for control of nuisance mosquitoes, and it was the product’s efficacy in this role that led to it becoming the preferred tool for use in control of vectors of West Nile virus.

The City of Edmonton’s mosquito control program is considered one of the leading edge programs in the country. Our systems of monitoring, mapping and notification, our equipment use and application techniques, and even our choices and methods of chemical use are amongst the best in North America. Our personnel are licensed by the Province and trained in specific mosquito control techniques. They have themselves invented a variety of novel and innovative technologies that increase the accuracy and efficiency of our pesticide delivery and reduce the amount of pesticide we need to apply.

We are involved in ongoing projects with Alberta Environment and Health Canada’s Pesticide Management Regulatory Agency, and supply data annually to support re-evaluation of the use of Dursban.

Control of nuisance species of mosquitoes increases the quality of life and enjoyment of the outdoors for all Edmontonians and those in the Edmonton area. By controlling mosquitoes in the aquatic larval stage with Dursban, we are able to avoid fogging for adult mosquitoes, and also reduce the chemicals that would be used by homeowners to control or repel the mosquitoes themselves.

We also work with the City’s Office of Natural Areas, and with the Drainage branch to preserve natural habitat and create more naturalized constructed facilities that encourage the development of populations of dragonflies, fish and other mosquito predators. At the same time, we also have a source reduction program that eliminates shallow depressions in schoolyards and residential areas that can become mosquito development habitat.

While Dursban is a broad-spectrum pesticide, we use it only on temporary habitats where mosquito larvae develop in large numbers, and there are few other organisms present. The amounts we use are also as low as we can apply it and still get effective control.

Especially in our northern climate, there are very few options for effective mosquito control. Most other available products do not work well in cold weather, or do not work on the species of mosquitoes we have here.

Dursban is also not the only product used in Alberta with chlorpyrifos as the active ingredient. It is widely used in agricultural applications, and the use of Dursban accounts for only 0.5 % of the total chlorpyrifos use in the province.

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