Stay Informed About Blue-Green Algae

29 October 2023

Some area lakes in Stouffville may have conditions that lead to blue-green algae blooms developing.

Blue-green algae is a type of harmful bacteria that can appear in bodies of water. These microscopic organisms, scientifically known as cyanobacteria, can pose risks to both humans and animals. While often blue-green in color, they might also appear olive-green or red.

Recognizing the Signs:

Normally unseen, blue-green algae can rapidly multiply under favorable conditions, forming dense clusters called blooms. You might notice these blooms near docks and shorelines during late summer and early fall. They thrive in warm, slow-moving, and shallow waters, but can also be present in deeper, cooler areas. A blue-green algae bloom can make water look bluish-green, like green pea soup, or even turquoise paint. Detecting a grassy or garbage-like odor in the water could also be a sign of a bloom.

Understanding the Causes:

The growth of blue-green algae is often fueled by available nutrients, particularly phosphorus. Sources of these nutrients include agricultural runoff, stormwater, and leaching from septic systems. In Ontario, phosphorus tends to be the main driver of algae growth.

Stay Safe:

While some blue-green algae are harmless, others can produce toxins that endanger human and animal health. If you suspect a blue-green algal bloom:

  • Assume toxins are present.
  • Refrain from using, drinking, bathing, or swimming in the water.
  • Keep pets and livestock away from the water.
  • Contact your local health unit for information on the associated health risks.

Report and Prevent:

If you spot blue-green algal blooms, contact the Spills Action Centre at:

Phone: 1-866-MOETIPS (6638477)

TTY: 1-855-889-5775

To prevent the growth of blue-green algae:

  • Opt for phosphate-free detergents and cleaning products.
  • Avoid using phosphorus-containing fertilizers on lawns.
  • Maintain natural shorelines on waterfront properties.
  • Minimize agricultural runoff by planting vegetation along waterways and reducing fertilizer use.
  • Regularly inspect septic systems to prevent leaks into water sources.

For more information visit lsrca.on.ca/Pages/blue-green-algae.aspx

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