Blue-green Algal Blooms: Cyanobacteria

What are Blue-Green Algae?

Blue-green algae, which can be found on the borders of lakes and ponds, are not actually true algae or plants, but are a type of microscopic organism call cyanobacteria. Their pigmentation gives them their blue-green color. Blue-green algae grow in summer in calm, warm, shallow water which is rich in nutrients (e.g. nitrogen and phosphorous).

Cyanobacteria are not always visible on the surface of the water. Generally, they become visible when they are present in large numbers in one particular area. When this happens, blue-green coloration becomes visible in and/or at the surface of the water (the color can vary from olive green to red). Eventually, foam may form on the surface of the water (see photos). The wind, the waves and the current have a tendency to disperse them, but hey might still reappear. The blooms may generate an undesirable garbage-like odor or an odor reminiscent of freshly-cut grass.

This is a problem that exists nearly all around the world and affects some lakes in the Monteregie area as well as other regions in Quebec.

What are the Health Effects?

Cyanobacteria and the toxins they produce may cause health effects. However, no cases of disease caused by blue-green algae have been reported in Quebec. Nevertheless, there may be a possibility that health problems have occurred in the past but went undetected or were confounded with other causes.

What do I do if I develop One or More of these Symptoms?

If you develop symptoms following contact with the contaminated water, immediately avoid further exposure to the water. Rinse your skin with clean water. If this occurs at a public beach, inform the person in charge of the beach.

If symptoms persist after a few days or your condition worries you, contact Info-Santé through your local CLSC or consult your doctor. Please note that these symptoms can be caused by problems other than cyanobacteria (e.g. fecal matter in the water, swimmer’s itch, etc.)

Symptoms

By Direct Contact
* Skin irritation
* Nose irritation
* Throat irritation
* Eye irritation

By Ingestion
* Stomach ache
* Diarrhea
* Vomiting
* Nausea

More Rarely
* Dizziness
* Headache
* Fever
* Liver damage
* Nervous system damage

Taken from Régie régionale de la santé et des services sociaux pamphlet August 2001

Pictures of blue-green Algae