Additional Results from August 29th and September 2nd Water Samples – September 27, 2022

Three Mile Lake Community.

On Thursday, September 22 we received information concerning the blue-green algae bloom affecting Three Mile Lake from the Ministry of Environment, Conservation and Parks (MECP).  The communication reported toxin levels from the samples taken on August 29th and September 2nd.

Some brief background information regarding cyanobacteria and cyanotoxins.

  • Blue-Green Algae is more correctly known as cyanobacteria
  • Some cyanobacteria can produce various cyanotoxins (toxins).
  • The cyanobacteria in Three Mile Lake produce microcystins and anatoxin. Microcystins are of greater concern.
  • The release of toxins in an algal bloom into the surrounding water occurs mostly during cell death and lysis (i.e. cell rupture)
  • Every governing body provides guidance with regard to microcystin exposure.
  • Health Canada’s guidance:
    • Total microcystins:
      • Drinking water: less than or equal to 1.5 micrograms per Litre (µg/L)
      • Recreational Use: less than or equal to 10 µg/L

The following toxin results were sent from MECP via email.  The toxin levels reported below are from the samples taken on August 29th and September 2nd.  As noted above, keep in mind toxin levels change as the bloom deteriorates and cyanobacteria die off.  These are point-in-time results.

 

The following are the results we received from our labs in regard to Three Mile Lake samples.

Location 1:  Cowan Rd. – West Basin

Results:

            • Total Microcystins – 0.12 micrograms per Litre (µg/L)
            • Total Anatoxin-A – below the detectible limit of 0.20 micrograms per Litre (µg/L)
            • Algal ID- Yes to a Cyano bloom – Algae condition was very deteriorated.
            • The most abundant algae in the bloom included blue-green algae; also known as cyanobacteria, which has the potential to produce toxins.

Location 2: Hammell’s Bay Three Mile Lake

Results:

            • Total Microcystins – below the detectable limit
            • Total Anatoxin-A – below the detectable limit
            • Algal ID – Yes to a Cyano Bloom – Algae condition was in deterioration
            • The most abundant algae in the bloom included blue-green algae; also known as cyanobacteria, which has the potential to produce toxins.

Location 3: Carlo Enterprise Road Three Mile Lake – East Basin

Results:

            • Total Microcystins – 0.13 µg/L
            • Total Anatoxin-A – Below the detectable limit
            • Algal ID – Yes to a Cyano Bloom – Algae condition was in deterioration
            • The most abundant algae in the bloom included blue-green algae; also known as cyanobacteria, which has the potential to produce toxins.

Barrie District

Ministry of the Environment, Conservation and Parks

 

It is important to note lakes are dynamic ever-changing environments and toxins are released after cyanobacteria die and decay.  These results will change over the course of the bloom.  Please continue to use common sense when using the lake.  We anticipate further testing by the MECP over the next few weeks.  We will communicate information as we receive it.

The following are links to Cyanobacteria publications for your reference.

Cyanobacterial Toxins in Drinking Water Health Canada

Guidelines for Canadian Recreational Water Quality – Cyanobacteria and their Toxins Health Canada

Blue-green Algae Government of Ontario

Learn about Cyanobacteria and Cyanotoxins United States Environmental Protection Agency

TMLA Board