Possible blue-green algae risk at Oakfield Beach

The Halifax Regional Municipality is advising the public to avoid swimming in the lake until further notice.

CITYnews halifax \ Tyler Dunne

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Haligonians are being asked to avoid swimming in the Shubenacadie Grand Lake due to the possible presence of blue-green algae.

A risk advisory has been issued for Oakfield Beach near Enfield.

Halifax Regional Municipality is encouraging users to take the following precautions:

• Avoid all contact with the mat material and surrounding water. If contact occurs, wash with tap water as soon as possible, and seek medical care
• Do not swim or wade (or allow your pets to swim or wade) in any areas where blue-green algae is visible or in areas where a risk advisory has been issued.
•  Avoid consuming fish that has come from this lake.
• Keep pets on a leash and away from the water in areas where a potential benthic mat has been identified.

“Blue-green algae (cyanobacteria) is naturally occurring in freshwater environments and may become visible when weather conditions are calm,” HRM stated in a news release.

“These organisms can multiply rapidly during the summer, leading to extensive growth on the lake bottom called a benthic mat. Some types of blue-green algae produce toxins during mat growth and when these mats decay, the toxins may be released into the water, posing a risk to people and pets.”

“Toxins found in benthic mats can be far more concentrated than those found in blooms. The mat material itself may also be toxic if consumed, and can be a particular risk for pets.”

“It’s highly toxic,” Bedford veterinarian Dr. Jeff Goodall told CityNews Halifax earlier this summer. “By the time your dog has contacted it, it’s probably going to be pretty bad. You need to seek immediate care.”

“Simply licking the scum coat could be fatal.”

Staff at HRM’s 18 supervised beaches are constantly on the lookout for blue-green algae.

Last month, Elizabeth Montgomery, a water resources specialist on HRM’s environment and climate change team, told CityNews Halifax if something looks suspicious, lifeguards will snap a photo and send it to her team.

If they can’t determine it’s something else like, like pollen, they will immediately close the beach and send a sample into a lab for analysis.

If the algae bloom is not toxin-producing, the risk advisory will be lifted and no further testing is required, but if the bloom is toxin-producing, the risk advisory will stay in place until results indicate the water is once again safe.

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.

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 — can be reported by calling 1-877-936-8476.

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

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.

A medium-density bloom of blue-green algae species in Nova Scotia, near the shoreline of a lakeNova Scotia Department of Environment and Climate Change