Blue-green algae bloom found in Yellowknife not toxic, government says

An algae bloom spotted last week in Great Slave Lake in Yellowknife has turned out not to be toxic.

Cyanobacteria or blue-green algae was reported on Aug.18 along the Rotary boardwalk in the city.

The N.W.T.'s Department of Environment and Climate Change and the Canadian Coast Guard tested samples from various locations in the area.

The results showed no toxins present.

"We found that there were no detectable levels of microcystis which are one of the main forms that are present during a cyanobacteria bloom if they are making them," said Jeffrey Cederwall, an aquatic quality scientist with Environment and Climate Change.

"Microcystins are livertoxins which can have an effect on people and animals in the water. So it's a really good news that we didn't find them within the water of these blooms."

Cederwall said the water quality alsomeets Health Canada guidelines for drinking and recreation, butit's best to exercise caution where these blooms are visible.

Cyanobacteria blooms continue to be reported in Yellowknife Bay and the North Arm, he said.

He also said that with the rains the city has been getting lately, there is a risk of larger cyanobacteria blooms in the Yellowknife Bay area.

He said run-off water can carry nutrients like phosphorus, used to help plants grow in gardens. If those nutrients reach bodies of water, it usually increases aquatic plant growth.

"When we have run-off events, like what we had from our rain, it can lead to run-off from our municipal drainage into the bay. So what we have on our streets and our area, that does end up in our bay. And that can help fuel larger blooms," Cederwall said.