Blue Green Algae Blooms

Wed, Aug 05, 2026

Algoma Public Health (APH) is reminding residents and visitors of Algoma that blue-green algae blooms are more common this time of year when water is warm, shallow and slow moving.  Blue-green algae, also known as cyanobacteria, are naturally found in fresh water.  They are often present in low numbers and barley visible, but 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, or itchy and irritated skin, eyes, nose and throat through direct contact or if inhaled.  Drinking large quantities 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 an alternative safe water source 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 the water safe to use.
• Do not bath 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

For more information, including a list of bodies of water historically impacted by blue-green algae, visit APH’s blue-green algae webpage.

 

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