Recreational Water Quality

Hi there, early this season, Nova Scotia Environment and Climate Change (NSECC) issued an advisory for Sherbrooke Lake, recommending that residents not use the Lake based on visual observation of algae that may have been of the blue-green type. Blue-green algae can pose a safety risk to users by exposing them to toxins sometimes found in the algae. The toxins can cause illness if ingested or irritation to skin and eyes.  Pets can ingest significant water when swimming or playing in a lake and therefore could be more at risk than people. 

Often, NSECC advisories are issued for entire seasons. This happens because 1) algae blooms can disappear and reappear at different locations on a lake depending on conditions, making them difficult to monitor; and 2) NSECC does not have the resources to monitor lakes regularly.

For the last three years, a group of volunteers on Sherbrooke Lake have been funded by the Municipalities of Chester (MOC) and Lunenburg (MODL) to sample and assess the lake water quality to establish baseline data for future comparison once MODL develops a public access site on the Lake. This year, in addition to this regular testing and in response to an increased number of visible algae blooms, the group was also funded to sample and assess for microcystin. Microcystin is the most common toxin produced by cyanobacteria (also called blue-green algae) but not the only one. Other toxins could be present. Samples are sent to an independent lab and results take several weeks. 

Taking all of these things into account - length of time for test results, potential for blooms to become toxic or disappear altogether - it's difficult to predict accurately whether residents can swim in the Lake at a given location at a given time.  However, we are not aware of any incidents of individuals swimming in the lake exhibiting the symptoms typical of toxic blue-green algae.

The only advice we can offer residents in terms of using the lake for swimming is to be aware of what algae blooms looks like, how they behave, and where they are located. Choosing to swim under a seasonal advisory is up to each individual to assess the risk.

If there is a bloom visible, please take pictures and notify NSECC. They will send a representative to visually assess. For additional information, you can find the sample results and reports on an open source data site found at https://atlanticdatastream.ca/

Of course, the best way to avoid a blue-algae bloom is to prevent prevent the nutrients – like nitrogen and phosphorous - that algae feed upon from entering the lake. Property owners should allow natural habitats to exist on their shorelines rather than lawns, eliminate the use of fertilizer, and be mindful with your own waste and animal waste. On a policy level, contact your Municipality about establishing environmental protections around lakefronts through zoning.

An informative video on blue-green algae can be found at https://www.youtube.com/watch?v=X-FDCyp9Erk. You can also find useful information at https://www.canada.ca/en/health-canada/programs/cyanobacterial-toxins-drinking-water/cyanobacterial-toxins-drinking-water.html

Yes, testing occurs regularly on Sherbrooke Lake. Your lake is a pilot location for water quality testing as a result of the proposed public access area. If you would like to sign up for information specific to Sherbrooke Lake, or get in touch with the community members of the Stewardship Committee, please reach out to Robin McAdam. I will direct message you with his contact information.