The CRD has issued an advisory for Elk/Beaver Lake Regional Park on Tuesday.
Water samples taken from Eagle Beach at Elk Lake, located within Elk/Beaver Lake Regional Park, have tested positive for a type of blue-green algae that can produce cyanotoxins.
Tests show no blue-green algae at Beaver Lake. Testing will continue at both lakes.
Authorities are advising visitors to avoid Elk Lake and to keep animals on a leash to prevent them from drinking or swimming in the water.
Algal blooms are known toxin producers and can be harmful to both humans and animals. While unpredictable, blooms typically occur over the winter months from November to March.
The algae usually produce a visible blue-green sheen, which appears as surface scum. However, not all blooms are easy to see and toxins can still be present in the water even if you cannot see them.
Ingesting water containing the algae may cause a range of symptoms, including headaches and abdominal pain in humans, and can lead to lethal liver damage in dogs.
