Water advisories were issued for Devonshire Beach on Lesser Slave Lake and Lac La Biche Lake Friday.
The province said “elevated levels of fecal coliforms” at Lesser Slave Lake’s Devonshire Beach mean no one should be swimming or wading there.
People are also warned not to drink the contaminated lake water, which could cause vomiting and diarrhea.
The contamination could also cause skin, ear and eye infections.
Another advisory was issued for areas of Lac La Biche Lake, where a blue-green algae bloom has been identified.
Residents living near the shores and visitors are asked to avoid all contact with the contaminated water.
People should avoid touching the algae bloom, swimming or wading in areas where algae can be seen. It’s also advisable to prevent pets from eating fish from the lake and consider limiting human consumption of the fish.
The province also reminded people not to drink or cook with untreated water from any lake.
Blue-green algae looks like scum, grass clippings, fuzz or globs on the surface of the water. It can cause skin irritation, rash, sore throat and eyes, fever, nausea and diarrhea. Symptoms usually appear within one to three hours of exposure and resolve within one or two days.
People can still use the lake in areas where no algae is visible.