Green-blue algae found in Yellowknife Bay has been tested and is not a risk to residents’ health.

On Wednesday, July 18, the Department of Environment and Climate Change (ECC) received a spill report of an unidentified, green-blue substance on Great Slave Lake near Negus Point on Yellowknife Bay.

An ECC inspector, along with a Coast Guard officer, observed the spill area and determined there was no fuel discharge.

Samples were collected and lab results found the substance to be a cyanobacteria bloom, a common, non-toxic type of algae, indicating the water remains safe. ECC is continuing to monitor the situation and is collecting additional samples in Yellowknife Bay and the surrounding area for further testing.

This year the combination of unusually warm water temperatures, less flow through the Yellowknife River, and the recent sustained south winds may have contributed to increased algae in Yellowknife Bay. Previous small algal blooms have been observed in Great Slave Lake near the Mirage Islands and in bays on the North Arm and may arise again through August or early September.

Residents and waterway users around Yellowknife Bay are advised to avoid swimming in the affected areas and to keep pets away. Collecting the water to treat for drinking and cooking is not recommended. Regular water use can resume once the algal bloom is no longer visible.

If you spot an algae bloom, you are encouraged to report it to the 24-hour Spill Report Line: 1-867-920-8130

For media requests, please contact:

Thomas Bentham

Senior Communications Officer

Environment and Climate Change

Government of the Northwest Territories

Email: thomas_bentham@gov.nt.ca

Phone Number:  867-767-9231 ext. 53042