Alberta Health Services warns against contact with cyanobacterial bloom at Matchayaw Lake
Blue-green algal toxins detected west of Edmonton; avoid swimming, wading, and do not drink or cook with lake water.
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Alberta Health Services issued a cyanobacterial bloom advisory Tuesday for Matchayaw (Devil's) Lake, about 60 kilometres west of Edmonton, after blue-green algal toxins were identified in the water.
The health authority lists several key precautions: do not swim or wade in areas where cyanobacterial blooms are visible. Avoid all contact with blooms in the water and material washed up on shore. If contact occurs, wash with clean tap water as soon as possible. Do not drink or cook with water from the lake. Do not eat whole fish or fish trimmings, as fish may store toxins in their liver — fish fillets contain less toxins and are safer to eat. Keep pets away from the water entirely and do not allow them to swim in affected areas or contact blooms.
"Cyanobacteria are naturally occurring and large growths called 'blooms' are more common during warm weather. Cyanobacterial blooms can be blue-green, greenish-brown, brown, pink and/or red, and can look like scum, streaks, grass clippings, fuzz balls, paint or pea soup," AHS noted. "They often smell musty or grassy."
People who come in contact with a cyanobacterial bloom or who ingest water containing cyanobacteria may experience skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea, vomiting and/or diarrhea. Symptoms can appear within one to three hours and resolve in one to two days. Symptoms in children are often more pronounced; all people are at risk. Exposure may be fatal to pets.
AHS warns that boiling the water will not remove the toxins. Anyone with health concerns is asked to call Health Link at 811.
By the numbers
Where is Matchayaw Lake and when was the advisory issued?
Matchayaw (Devil's) Lake is located about 60 kilometres west of Edmonton. Alberta Health Services issued a cyanobacterial bloom advisory on Tuesday, August 11, 2026, after blue-green algal toxins were identified in the water.
What should you avoid at Matchayaw Lake?
Do not swim or wade where cyanobacterial blooms are visible, avoid contact with blooms or material washed up on shore, do not drink or cook with lake water, and keep pets away from the water entirely.
How long do symptoms from cyanobacterial exposure last?
Symptoms can appear within one to three hours of contact or ingestion and typically resolve in one to two days.
