Cradled between hills and rivers

Blue-green algae

Exercise caution!

Blue-green algae, also known as "cyanobacteria", are bacteria that occur naturally in Quebec bodies of water. They spread especially in the summer. When they become too abundant, blue-green algae form blooms, which can spread over a part or the entire body of water.  The water turns green, and its texture becomes similar to that of paint or broccoli soup. Scum can also appear on the surface of water contaminated by blue-green algae. Generally, it is when you start to see scum that blue-green algae can become harmful to your health.


Do not drink this water.
Do not touch this foamy substance.
Do not go swimming in this water.
Keep children away from the affected area.

In non-affected areas, you can continue practicing aquatic or boating activities as normal, unless otherwise stipulated.

Effects on Health

Some blue-green algae produce a toxic substance that can result in health problems. For instance, a person may experience symptoms of gastroenteritis or experience irritation of the skin or throat after drinking water contaminated by blue-green algae or after coming into contact with it.

FOR MORE INFORMATION OR TO REPORT AN AFFECTED BODY OF WATER, DIAL 1-877-644-4545 or consult the following Website:



Source Ministry of Health and Social Services