Algae Blooms

Toxic algal blooms threaten Canadian drinking water, but scientists are developing a way to protect against the harmful slime.

Dangerous, slimy mats of blue-green algae are plaguing Lake Erie and other lakes across North America, not only interfering with ecosystems and recreational activities, but also complicating municipal water treatment processes.

Blue-green algae are microscopic bacteria found in freshwater, also called cyanobacteria. When certain types of cyanobacteria multiply under the right conditions, they can form thick toxin-producing scum.

Cyanotoxins can be deadly if they’re consumed by dogs and other animals. In humans, exposure can lead to symptoms ranging from mild to life-threatening: rashes, eye irritation, headaches, fever, vomiting, diarrhea, and liver or kidney damage.

There’s mounting pressure to tackle the threat, as blooms encroach on lakes across the country including in British Columbia, the Prairies, the Great Lakes, Quebec and Nova Scotia, where cyanobacteria blooms likely killed two dogs. Blue-green algae blooms have also popped up in unusual spots like Lake Superior and beaches in Hamilton, where local authorities say blooms used to be rare — if not unheard of.

The problem is well-known in waterfront communities in Southwestern Ontario. The amount of cyanobacteria in Lake Erie has been getting worse since the 2000s, according to the U.S National Oceanic and Atmospheric Administration (NOAA).

In Lake Erie, the main culprit of the blooms is phosphorus-rich runoff from agriculture and urban pollution — the bulk of it coming from the United States. That, combined with the lake’s shallow, warm waters creates the perfect habitat for the dangerous scum to thrive.

Canada and the U.S. have strived to improve Lake Erie’s water quality since the 1970s, and most recently committed to reducing phosphorus loads by 40 per cent from 2008 levels.

Yet the pollution persists, and the recurring blooms threaten a lake relied on by about 12 million people for drinking water.

(content courtesy of The CBC and The Globe and Mail)