THUNDER BAY — The Thunder Bay District Health Unit reports that no toxins were detected in a sample of blue-green algae taken in late August from Madelaine Lake, about 100 kilometres west of Thunder Bay.
The results of the analysis in a provincial laboratory were released Monday.
Some blue-green algae produce toxins that pose a health risk to people and animals.
This summer, the presence of the algae was confirmed in four lakes in the District of Thunder Bay.
Toxin tests were negative for a water sample from Warnica Lake, and indeterminate for a sample from Icarus Lake.
The only test result still outstanding is for Surprise Lake, where a water sample was taken on Sept. 16.
The TBDHU cautions that testing for toxins only identifies whether a blue-green algae bloom was producing toxins at the time the sample was taken.
A negative result does not mean the bloom is not harmful.
Blue-green algae can turn toxin production on and off in response to a variety of environmental factors, meaning that toxins may be produced at different times during a bloom event.
