April 16, 2015, 9:29 a.m.
EDMONTON - City crews fighting mosquito larvae have been using a restricted insecticide inside city limits, 30 metres from people’s homes and in natural areas such as Terwilliger Park.
The new details are coming out after a volunteer group, Pesticide Free Alberta, fought to get copies of Edmonton’s application records for Dursban 2.5, concerned people might be hurt by a product they don’t even know is being used.
Even though Health Canada recommends municipalities use the Dursban in “outlying areas,” where no children could come in contact with it, the city data shows places across the city where it has been used.
As helicopters took to the skies again this week, city officials said they will be using Dursban again this year.
“The same way its been used for the past 10 years,” said David Aitken, branch manager for community standards. “Health Canada allows us to use it. We follow the directions on the label and right now council supports the mosquito program.”
Edmonton is the last municipality in Canada to still use the product, a neurotoxin that can affect brain development. Winnipeg phased it out this year. Edmonton bought Winnipeg’s remaining supply for $79,600.
Health Canada says the light, dry pebbles applied by workers on the ground or dropped from a helicopter are not to be used near any home or in places such as parks, school grounds or playing fields. The Health Canada Consumer Product Safety sheets limit it to killing mosquito larvae in “temporary pools in outlying areas of municipalities” to lessen the potential for human exposure.
But the City of Edmonton says the chemical label allows Dursban to be applied in industrial areas, road allowances and undeveloped land. Edmonton’s 2014 applications appear to include industrial land butting up against residential neighbourhoods, golf courses, road allowances and Terwillegar Park.
“Terwillegar Park. It’s all scrub, undeveloped,” said Al Dalman, team leader in the pest management group.
City flight records put helicopters above or near Terwillegar Park five times last year, but pilots didn’t keep a permanent record of whether Dursban was dropped in any one location.
“This Dursban, nobody knows. Every time I show people, they’re like, ‘Wow, I don’t believe this,’” said Sheryl McCumsey, co-ordinator for Pesticide Free Alberta, the 20-year-old, not-for-profit organization. “This insecticide is really nasty. It doesn’t just go away nicely a few weeks later.
“They shouldn’t be spraying at all in the city,” said McCumsey, worried people would mistake symptoms of exposure for sunstroke.
McCumsey fought for months to get the data.
She originally asked for the pesticide application records last June, only to be told no for privacy reasons. She submitted a formal freedom of information request. When that was denied, she appealed to the provincial privacy commissioner.
She went back to the commissioner when the first records she got had locations blacked out.
Some data are still missing. In 110 cases, the city crews failed to record enough information to pinpoint which grid location was visited. In 131 cases, city staff recorded a grid location, but not if Dursban or a safer biological option was used.
Aitken said Edmonton uses Dursban for its initial spring program when it’s too cold for VectoBac, the more expensive bacteria-based alternative, and then continues to use both Dursban and VectoBac during the rest of the summer.
The city also use Pyrate, an insecticide with the same active ingredient as Dursban, along roadside ditches.
Aitken said his office will improve record keeping this year and consider posting all the records online.
As for phasing out the chemical, “someone has to be the last person to use it,” he said. “It’s about increasing livability in Edmonton so we can enjoy our summers.”
Each point marks the centre of a mile-by-mile square. Yellow diamonds indicate ground crews applied Dursban 2.5 somewhere in that square. Red pointers indicate a helicoptor pilot checked that square for temporary bodies of water and may or may not have treated the location. Click on each marker for more information. Mobile users can access the map here http://tinyurl.com/mrbhgqn.
What is Dursban? And how have other cities dealt with mosquitoes?
What is Dursban 2.5?
Health Canada banned residential use of Dursban and its active ingredient chlorpyrifos in 2000. Chlorpyrifos is an organophosphate and neurotoxin that can affect the nervous system and a child’s brain development. It’s toxic to fish, bees and many aquatic organisms.
After a 2007 review, Health Canada continued to allow its use against mosquito larvae at the request of municipalities in Manitoba and Alberta. Dow AgroSciences stopped making the product in 2011 and the registration was set to expire December 2014. The deadline was extended to December 2018 last fall.
Edmonton has enough stockpiled for two years.
Calgary has been using a bacterial product for at least 15 years, said Lincoln Julie, habitat management superintendent for Calgary Parks.
“We started using it because there were products coming on the market that were environmentally sound,” he said of the corn-husk based product with naturally occurring bacteria. It floats on the surface of the water until the mosquito larvae eat it.
“It’s very specific to just mosquitoes. It’s based on the PH,” he said. “We find it’s very effective.”
Calgary treats the perimeter of the city by helicopter in one major blitz, usually in mid-May. The city has a four- to five-day window to get the product on the water before the mosquitoes start hatching. Edmonton’s pest management team says it would have to start its mosquito campaign several weeks later and use four helicopters rather than two if it followed Calgary’s example.
Winnipeg city council voted in 2005 to phase out Dursban, first inside city limits and then in the surrounding countryside. For Taz Stuart, the former city entomologist who proposed the plan, the issue was environmental.
“With a chemical program, it’s non-selective,” he said. “You take out everything. What comes back first? Mosquitoes.”
During the summer of 2005, the city had the highest mosquito counts on record. Since then, the numbers have been lower, he said, crediting VectoBac, the same bacteria-based solution Calgary uses. “I was trying to build up the natural (predator) population.”
Winnipeg also has an adult mosquito fogging program for bad years.
Edmonton’s team says it maintains dragonfly and other predator populations by not spraying permanent bodies of water.