UPDATE: Testing confirms algae growth not toxic

Thursday, April 9, 2020

Update: Thursday, April 9, 7:45 PM

Laboratory tests on samples of algae taken from a bloom on Shuswap Lake show that the substance in the water is not toxic to people or pets. 

As a result, Interior Health has lifted the health warning put in place earlier in the day.

It was initially suspected that the bloom was Cyanobacteria (commonly known as blue-green algae)​ which can be poisonous if swallowed by people, pets or livestock.

As a result, Interior Health and the CSRD immediately issued a health warning to the public advising against ingesting or otherwise coming into contact with the substance. 

Tests of two samples were returned to Interior Health and the CSRD on Thursday evening. Analysis of the samples determined the algae and organic matter is not Cyanobacteria (blue-green algae). Therefore it poses no risk to the public. 

That being said, Interior Health advises against drinking untreated water from lakes, ponds or wetlands at any time.

No other potentially harmful types of algae were detected in the samples. 


Original Post, Thursday April 9, 12:30 PM

A suspected blue-green algae bloom in Shuswap Lake southwest of Herald Provincial Park is prompting a warning from Interior Health. 

Effective immediately and until further notice, the public is advised not to drink water directly from the lake in the vicinity of the bloom site and should avoid touching the algae, which has partially washed up on shore near Ashby Point, southwest of Herald Park. 

Citizens should not wade or swim in the area of the bloom and should prevent pets from ingesting any water or swimming nearby. They are also advised not to fish or consume fish caught in the area.

The bloom, which is suspected to be Cyanobacteria (commonly known as blue-green algae), is a mass of approximately 30 metres wide. Please see the attached map at right for more detail. Testing is underway.

It is not known how long the area will be affected.

Some blue-green algae blooms can produce chemicals that are poisonous if swallowed by people, pets or livestock. Blooms can cover the surface of the water and may look like thick pea soup. Not all blooms, however, are easy to see. Toxins can still be in the water even if you can not see the bloom.

If ingested, symptoms of exposure to blue-green algae can include headaches, nausea, fever, sore throat, dizziness, stomach cramps, vomiting, diarrhea, muscle aches and blistering the mouth and lips. If you have been exposed to blue-green algae and have symptoms, contact your health care provider right away.

More information can be found at the HealthLinkBC file No. 47 at this link:


If you have concerns, or wish to report possible algae bloom activity, contact the Report a Poacher or Polluter line (RAPP line) at 1-877-952-7277 (RAPP) or #7277 on the TELUS Mobility Network.

View Media Release


Top: A close up image of the algae bloom in Shuswap Lake near Ashby Point.

Below: A photo of the area in Shuswap Lake in Electoral Area C, which has been affected by an algae bloom. The dark shadow in the water is the algae. People are warned to keep themselves and their pets away from the substance. (Interior Health photos)