THUNDER BAY — The Thunder Bay District Health Unit says blue-green algae has been identified at Trout Lake.
TBDHU announced Wednesday that the Ministry of the Environment, Conservation and Parks confirmed the presence of the algae in a water sample collected from the Gorham Township lake on Aug. 31.
Blue-green algae may contain toxins that are harmful to human health.
TBDHU said it's important to note that water should be avoided whenever a blue-green algae bloom is present, and for about two weeks after a bloom has dissipated.
This is the sixth time this summer that blue-green algae has been found in a Thunder Bay-area lake.
Lab tests from the first two cases found that toxins in the algae were at levels that were below the Ontario drinking water standard.
However, TBDHU has since stopped reporting toxin analysis results.
In a statement to TBNewswatch, the health unit explained its rationale.
It said some members of the public were under the impression that they should wait for the toxin analysis of the algae before taking action to avoid water with a bloom, or that if the toxin analysis was negative, then there was no problem.
"That is not the case," the TBDHU statement clarified. "Testing for toxins can identify if the bloom is producing toxins at the time the sample was taken. However, a negative result does not mean that the bloom is not harmful. Blue-green algae can turn production on and off in response to a complex suite of environmental factors"
It added that it is reporting blue-green algae blooms so that people who regularly use a lake are aware of its potential to generate blooms.
"However, there is a delay between when a potential bloom is reported and when it is confirmed [by environment ministry lab tests]. This means lake users should not rely on our notifications alone, but rather should observe the lake at the time they wish to use it, and take avoidance precautions if they see or smell what may be a harmful blue-green algae bloom."
