Nova Scotia

Expert says blue-green algae may not be cause of Grand Lake contamination

A Dalhousie University professor does not think blue-green algae is to blame for the contamination at Grand Lake, N.S., which led to the deaths of two dogs and sent a person to hospital last week.

Provincial test results are expected back on Tuesday

Prof. Tri Nguyen-Quang of Dalhousie University is seen in the lab in this file photo. Nguyen-Quang says based on his own Grand Lake testing, he did not find any evidence of blue-green algae bacteria. (Dalhousie University)

A Dalhousie University professor does not think blue-green algae is to blame for the contamination at Grand Lake, N.S., which led to the deaths of two dogs and sent a person to hospital last week.

Tri Nguyen-Quang, an engineering professor whose research includes water quality and management, collected samples of the lake water around the shoreline last week. 

"I think there is some very harmful substance, chemical substance in the water. But that I don't know yet," Nguyen-Quang said Monday. "So far, just the impression that … something is not normal there."

Nguyen-Quang tested the water after gathering samples June 11 between 4 p.m. and 5 p.m., and determined there was no evidence for cyanobacteria or the toxins they produce. Blue-green algae is caused by cyanobacteria.

The professor said he didn't see any visible algae blooms during his visit. However, Nguyen-Quang said he spotted fish, including many that appeared to be in poor health, moving en masse into Grand Lake from nearby Fish Lake. Some appeared to be dying.

"Under my point of view in ecology, there would be some problem there in the lake, Fish Lake," said Nguyen-Quang, who teaches at Dalhousie's Agricultural Campus in Truro.

He added that could explain why fish were migrating so quickly into Grand Lake.

The province is treating the incident as a suspected blue-green algae bloom based on visual evidence from the time the complaint about water quality was made.

An alert was issued Thursday morning warning all residents who take water directly from Grand Lake to stop using the water immediately.

An area of Grand Lake near Fall River is seen on Thursday, June 10. A water advisory warning people to not use water from the lake, or go into it, was still in effect Monday. (Paul Palmeter/CBC)

The province said test results are expected Tuesday from the Grand Lake and Fish Lake water samples. The tests look for contaminants that can be found in pesticides, toxins produced by algae, and E. coli.

Residents near Grand Lake who don't receive water from a municipal utility are still advised not to consume their water, or use it for cooking, bathing, swimming or boating, until told otherwise.

The advisory includes anyone who has a shallow drilled or dug well that is less than 30 metres deep and is within 60 metres of the lake.

The East Hants Aquatic Centre is open in the morning and afternoon for people who want to take a shower, fill up containers of drinking water or pick up free bottled water.

More than 120 people drop in for showers, drinking water

Carla Countway, aquatic co-ordinator for the Municipality of East Hants, said Monday they've had over 120 people drop into the centre to use the services so far.

Halifax Water and the East Hants Regional Municipality have confirmed their water systems are not affected by the advisory, but some people in the area are still worried.

Richard Sherman, 78, dropped by the centre Monday for a box of bottled water, even though his home is on the East Hants municipal system. 

He said while he's comfortable bathing and washing clothes in the water, drinking it is a step too far for now.

"[We] just don't trust the taps," Sherman said.


  • An earlier version of this story contained a photo of a blue-green algae bloom. The photo had been provided by the Nova Scotia government, which said it had been taken at Grand Lake on June 9 by Halifax Regional Fire & Emergency. In fact, the photo shows a different lake and was not taken by Halifax Fire. It has been removed from the story.
    Jun 15, 2021 2:17 PM AT

With files from Jack Julian