Blue-Green Algae Confirmed In Boyd Bay / Indianhead Harbour Area Of Lake Muskoka

Photo taken Aug 17th at Indianhead Harbour on Lake Muskoka.

The Simcoe Muskoka District Health Unit would like to inform residents and visitors that a blue-green algae (cyanobacteria) bloom has been confirmed by laboratory testing in the Boyd Bay / Indianhead Harbour area of Lake Muskoka. The health unit advises that human or animal consumption of this lake water should be avoided.
If you are drawing your water from this area of Lake Muskoka, boiling the water will not destroy toxins and home treatment devices may not be effective for their removal. Until further notice, do not use the water for drinking or for food preparation including breastmilk substitute (infant formula). Safe water sources include municipal water, bottled water or a good well that is not affected by lake water. The health unit and the Ministry of Environment, Conservation and Parks (MECP) will continue to monitor and test the algal bloom and you will be notified when the water is safe for use.

The health unit advises residents and businesses not to drink the water from this lake and to take the following precautions:
 do not use the lake water for drinking or for food preparation including breastmilk substitute (infant formula), even if it is treated or boiled
 do not cook with the lake water because food may absorb toxins from the water
 do not allow pets or livestock to drink or swim in the water where an algae bloom is visible
 do not eat the liver, kidneys and other organs of fish caught in the lake. Be cautious about eating fish caught in water where blue-green algae blooms occur.
 do not use herbicides, copper sulphate or other algaecides that may break open algae cells and release toxins into the water
 avoid swimming and other water sport activities where an algae bloom is visible (water may appear discoloured or have a surface scum)

Some blue-green algae produce toxins that can pose a health risk to people and animals when they are exposed to them in large amounts. Stop using the water and seek medical attention if symptoms such as skin, eye or throat irritation, allergic reactions or breathing difficulties occur while in contact with untreated surface water. Swimming, bathing or showering with water not visibly affected by a blue-green algae bloom is not expected to cause health effects.
Blue-green algae blooms may make the water look bluish-green, or like green pea soup or turquoise paint. Anyone who comes into contact with blue green algae should wash with soap and water or rinse thoroughly with clean fresh water.
The health unit and the MECP will continue to monitor and test the algal bloom and updates will be provided on our website ( as we receive new information.


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