Alberta Health Services has issued a blue-green algae bloom advisory for Islet Lake, east of Edmonton.
AHS says those visiting the lake should avoid all contact with algae blooms, including swimming and wading. It also advises against humans or pets eating fish or fish trimmings from the lake.
Visitors are also reminded that boiling the lake water will not remove the toxins produced by blue-green algae.
Blue-green algae is naturally occurring and often appears as scum, grass clippings, fuzz or globs on the surface of water.
Those that come in contact with or ingest visible blue-green algae can experience skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea and vomiting or diarrhea.
Symptoms are more pronounced in children and usually appear within one to three hours.
AHS says because weather and wind conditions can cause algae blooms to move from one location in the lake to another, the advisory will remain in effect for Islet Lake until further notice.
It notes areas of the lake where blue-green algae bloom is not visible can still be used even as the advisory remains in place.
Islet Lake is located about 55 kilometres east of Edmonton , or about a 20 minute drive northwest from Tofield.