Cyanobacteria (blue-green algae)

The departments of Health and Environment and Local Government work together to ensure that any suspected bloom is evaluated and that an advisory is posted when necessary.

Once issued, the advisory remains in place indefinitely.

Cyanobacteria may occur anywhere within a waterbody that has an advisory, such as a lake or river segment. Although there may not be an active cyanobacteria bloom, advisories remain on the list so the public is aware that blooms have been reported in the past. Bodies of water with a history of cyanobacteria blooms are at greater risk of future blooms. Also, toxins may remain in the water for several weeks after blooms are no longer visible.

Advisories help people make informed decisions about recreational activities on or in the water.  Since conditions may change in a matter of hours, it’s important to be aware of local conditions. You should always check the water and scan the shoreline before engaging in activities such as swimming or wading.

In New Brunswick, there are two types of cyanobacteria blooms to watch out for—surface blooms and benthic mats.

A surface bloom looks like scum or foam and can be blue-green, red, brown or green. Fresh surface blooms often smell like newly mown grass while older blooms sometimes have a foul smell, like garbage. On windy days cyanobacteria blooms may accumulate near the shore.

Benthic mats grow on the bottom of rivers and lakes and are an essential part of our freshwater ecosystem. These mats look like clumps of vegetation and appear black, brown or dark green in the water. On the shoreline they may appear brown or grey once dried.

Benthic mats may break away and wash up along the shore, making them accessible to pets and children. They can also be attached to rocks or aquatic plants.

Children and pets should not play with mats, as they may be lethal.

To assist department staff in addressing your concerns, it would be helpful if you could provide the following information:

• the name and location of the affected body of water
• photos, if possible, especially of the bloom’s colour
• if the bloom is on the surface or seems distributed lower in the water
• if the bloom is mainly along the shoreline
• the length of time the issue has been occurring

While not all cyanobacteria are harmful, some can produce toxins, which may cause skin, eye and throat irritations. More serious health effects such as gastrointestinal illness can occur if toxins are consumed.

The public is encouraged to be active and enjoy the outdoors, but to also be alert and take precautions:

• always supervise children and pets near water
• always check the water and avoid swimming in areas with visible surface blooms, scum or benthic mats
• do not enter the water with open cuts or wounds
• always wash your hands before eating
• do not use water from areas with cyanobacteria blooms for washing, drinking or cooking. boiling the water will not remove toxins. Always obtain drinking water from a clean and safe source.
• fish caught from water where cyanobacteria blooms are present should have all their organs removed and be rinsed well with clean drinking water before being cooked and eaten.
• even if no cyanobacteria blooms are present, shower with clean water after being in the water. Toxins can remain in the water for several weeks after surface blooms are no longer visible.

If you begin experiencing symptoms you should seek advice from a health-care provider.

Some cyanobacteria produce toxins that can harm an animal’s liver and brain. Dogs are attracted to the odour and, if ingested, they may:

• vomit 
• have a seizure
• experience breathing difficulties
• have diarrhea
• collapse and become unconscious
• die

Call a veterinarian if you suspect cyanobacteria poisoning.

To protect your pet:

• never let dogs drink or swim in water where visible blooms or mats are present
• never let dogs eat benthic mats or vegetation floating in the water or along the shore
• on hot days, consider walking your dog in the morning or evening
• always take fresh water for you and your dog

Although nutrients naturally occur in bodies of water and are needed for plant and animal life, too much phosphorus and nitrogen can offset the natural balance of a lake or pond. These problems arise or are compounded when storm water, agricultural runoff, industrial and wastewater effluent, faulty septic systems and lawn fertilizers find their way into bodies of water.

We all play a key role in the prevention of blooms by keeping excess nutrients from entering the water. Homeowners can:

• maintain a buffer of natural vegetation (trees, shrubs) along bodies of water to filter run-off and provide shade to keep the water temperature cool
• avoid using fertilizers and herbicides near water
• use phosphate-free cleaning products
• maintain your septic system and locate it far from the shore

Cyanobacteria — ACAP Saint John – Atlantic Coastal Action Program Saint John has been working with a collaborative group of organizations, researchers and the government to advance our understanding of cyanobacteria within the Wolastoq watershed.