Peterborough Public Health has detected blue-green algae blooms in a county lake, but it won’t reveal which one. Neither will the Ministry of Environment, Conservation and Parks.
The algae bloom was confirmed on June 29 according to Julie Ingram, Peterborough Public Health’s environmental manager. Testing in the lake revealed the “level of toxin did not exceed the drinking water quality standard,” she says, but this doesn’t mean it’s safe to drink—the toxins may have increased to dangerous levels since the lake was first tested.
Ingram was unable to provide the name of the specific lake, saying the MECP, which handles sampling, testing, and data collection, is responsible for the public announcement.
“The MECP would notify relevant stakeholders, which could include the local public health agency, local municipalities, and possibly local cottage associations,” she says. For this bloom, “Peterborough Public Health has done the usual direct and targeted outreach to affected public beaches or children’s camps.”
When asked for comment, the MECP could not provide the name of the lake. It instead deferred to the local public health unit.
Terry Rees, the executive director of the Federation of Ontario Cottagers’ Associations, says that FOCA wasn’t informed about the location of the blooms. He found the public reports “terribly unhelpful” as a result.
“Since these instances can be quite localized and they can come and go, it’s really important that people understand where exactly it occurred,” he says. “While we want people to be vigilant about the blooms, they shouldn’t be just completely paranoid about them all the time.”
Norman Yan, a research scientist who worked with the MECP for 25 years, says the ministry might be withholding the lake name to avoid upsetting property prices.
“There’s evidence in half a dozen studies that there are short-term impacts on property values and residences bordering lakes with recent algal blooms,” Yan says. “One local realtor in Muskoka thought that property values could decrease by 20 to 30 per cent over a year and a half.”
The many side effects of blue-green algae are the main concern for property owners. Direct contact with water that has blue-green algae blooms can cause rashes or eye irritation, and prolonged exposure can damage the liver. Ingesting the water can cause vomiting, diarrhea, or death in extreme cases, especially for dogs who drink affected lake water.
For cottagers who want to prevent blue-green algae blooms on their own lakes, Ingram recommends using phosphate-free detergent and soap, avoiding building stone walls near the water, and monitoring your sewage system regularly. If you’re gardening, avoid using nutrient-dense fertilizer and maintain the natural plants or grass around your property. These measures will all limit the algae’s access to the phosphate nutrients it thrives on.
But limiting the growth of blue-green algae has proven difficult recently. Yan says the rate of blue-green algae bloom is increasing again, even though these kinds of measures have been followed for the last few decades. Blooms are even appearing in lakes near Algonquin Provincial Park where the nutrient load isn’t typically suitable for blue-green algae.
Yan says hotter temperatures caused by climate change reduce the amount of wind near the surface, a phenomenon called “wind stilling.” This keeps nutrients in the same body of water for longer and allows blue-green algae to bloom later in the summer than usual, so they don’t need as much phosphate to survive.
“We’re getting another 20 to 25 lakes in Ontario that are having a novel algal bloom that didn’t used to happen,” Yan says. “We thought we had this one right, but we were wrong.”
To spot blue-green algae on a lake, check for water that looks like green soup and smells like a wet lawn. It can be difficult to tell it apart from native, harmless algae, so Ingram and Rees recommend reporting any algae you’re suspicious about to Ontario’s Spills Action Centre, your local health unit, and the MECP.
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