Potential Blue Green Algae Bloom in Upper Island Lake

Wed, Sep 17, 2025

 

Algoma Public Health (APH), in consultation with the Ministry of the Environment, Conservation and Parks, is advising residents and visitors of a potential blue-green algae bloom in Upper Island Lake, located in Aweres Township, north of Sault Ste. Marie. Blue-green algae blooms have been confirmed in this lake in the past. 

Blue-green algae are naturally found in freshwater lakes. They are often present in low numbers and barely visible.  When conditions are right, they can increase in numbers to form a scum called a bloom.  

Not all blooms are harmful, but some types of blue-green algae produce toxins that can make humans and animals sick when breathed in, swallowed, or touched.  Symptoms may include headache, fever, vomiting, diarrhea, and abdominal cramps if swallowed; if touched or inhaled, it can lead to itchy and irritated skin, eyes, nose, and throat.  Drinking large amounts of contaminated water over a long period of time may lead to more serious health effects, including damage to the liver, kidneys, or nervous system.

As a precautionary measure, APH recommends the following if a bloom is observed:

• Do not use the water for recreational activities such as swimming or water skiing. 
• Do not drink the water or use it for food preparation.
• Use alternative safe water sources such as bottled or municipally treated water.  Residential water treatment devices cannot remove the toxins.  Boiling or adding bleach to the water increases the amount of toxins and does not make it safe to use.
• Do not bathe or shower in the water.
• Do not let pets or livestock use the water for drinking or wading.
• Do not eat the liver, kidneys, or other organs of fish caught in the water.

 

More information about blue-green algae can be found on our website at: algomapublichealth.com/bluegreenalgae