Blue green algae a growing problem in HRM

Blue-green algae are a growing problem in the Halifax Regional Municipality.

A water resources specialist on HRM's environment and climate change team says the cyanobacteria are naturally occurring in Nova Scotia's lakes and rivers, but officials have seen an increase in the number of blooms in recent years.

“That's largely due to increased nutrient inputs into our lakes from development, and just people living around them and using them, and also due to warming lake waters and river waters due to the effects of climate change,” Elizabeth Montgomery told CityNews Halifax.

Blue green algae can harmful be humans — potentially causing cause skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea and vomiting and/or diarrhea — but they're often deadly for pets.

Late last week, HRM issued a risk advisory for Shubie Park Beach's off-leash dog area due to a potential bloom at Lake Micmac.

People are being encouraged to avoid swimming in and taking their pets near the lake until further notice.

As of Monday morning, HRM's supervised beach in Shubie Park on Lake Charles remains open. 

Montgomery said staff are constantly monitoring the water quality at all of HRM's 18 supervised beaches throughout July and August, so if a beach is open, she's confident the water is safe for swimming.

“All of our lifeguards have training, and if they see anything at all that is suspicious to them, we respond immediately,” she stated.

“We are monitoring all the time at the beaches we supervise,” she added. “Just because something was fine yesterday, or even this morning, doesn't mean it's going to necessarily not be affected later in the afternoon, and just because you see blue green algae in a particular part of the lake does not mean its not safe to swim in a different part of the lake.”

If something looks off, the first step is for the lifeguards to snap a photo and send it to HRM's environment and climate change team. 

“A lot of the time it turns out to be pollen or something, but if we can't rule it out just by looking at it … we'll close the beach right away and take a sample and send it to a lab for analysis,” Montgomery explained.

That analysis will confirm if it is blue green algae, and if so, if it is toxin-producing.

“If he reports back to us that whatever is present is not toxin-producing and we're confident it's fine, we reopen the beach and we alert the public,” she added. “If it is toxin-producing, we send further samples out to a lab in Ontario.”

A process, she said, that is expensive and time consuming.

“Once we get those results back, it will either tell us it's safe for swimming or it's not, then we'd just continue to test until we see the level is safe for swimming.”

When it comes to water quality outside of HRM's 18 supervised beaches, Montgomery said that's provincial jurisdiction, but with more than 1,000 lakes in HRM alone, not all of them can be constantly monitored. 

That's why Nova Scotians are being encouraged to learn how to identify blue green algae themselves and be on the lookout for them as they explore the province this summer.

Montgomery said the province is relying on members of the public to notify them of potential blooms — which form on and below the water's surface — and mats — which grow on the bottom of rivers and lakes or attached to structures and plants in the water — by calling 1-877-936-8476.

The province maintains a list of potential blue-green algae blooms online.

“They do some triage when someone calls in … they try to rule it out, but they're not verified,” she said. 

“Exercise caution and pay attention to what the province is reporting, but if you're seeing that the province has reported blue green algae, for example on Sandy Lake, which happened earlier this summer where we operate a beach, the public can be sure that, at that beach, if it's open, we're confident it's safe because we're doing our own monitoring.”

Despite the name, according to Nova Scotia's Department of Environment and Climate Change, the algae can be a variety of colours, including turquoise, green, brown, red, white or mixes of those colours. 

“Blue-green algae blooms can look like fine grass clippings in the water, spilled paint or pea soup,” the department said on its website. “Sometimes they look like a thick scum on the surface.”

Along the shore, they can dry up and appear brown or grey. 

Algae mats at the bottom of clear shallow areas look like clumps of vegetation and can appear black, brown or dark green in the water.

“They often smell musty or grassy when healthy and like ammonia when decomposing,” the department stated, adding animals can be attracted to that odour.

More information on blue green algae can be found on both the province's website and HRM's website.

Haligonians can find the status of their favourite municipal beach by clicking here.