Alberta Health Services has issued an advisory for Isle Lake after Cyanobacteria, also known as blue-green algae, was identified.
People living near or visiting the lake should avoid all contact with the blue-green algae blooms and are urged not to swim or wade in areas where they can be seen.
AHS said it can cause several symptoms including: skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea, vomiting and or diarrhea.
Symptoms will typically appear within a couple of hours and can be more pronounced in children.
If contact does happen people should wash with tap water as soon as possible.
AHS also encourages people to limit fish consumption from this lake but that fish should not be given to pets.
Pets should also be prevented from swimming or wading in areas of the lake where blue-green algae is present as exposure may be fatal.
Health officials say pets and livestock should be given an alternate source of drinking water while the advisory is in place.
The cyanobacteria will like scum, grass clippings, fuzz or globs on the surface of the water and occurs naturally, becoming visible when conditions are calm. It can appear blue-green, greenish-brown, brown or pinkish-red in colour.
Weather and wind can move the algae blooms from one location in the lake to another.
AHS said areas where the bloom is not visible can still be used for recreational purposes even while the health advisory is in place.