Harmful Effects of Blue-Green Algae

Algae are tiny plant-like organisms that live in damp areas, and are very common in ponds and lakes, where the water is still or shallow. "Blue-green algae," also called "pond scum," is the common term for cyanobacteria (Greek for "blue bacteria"), a strand of bacteria that use photosynthesis, the process through which carbon dioxide is converted to organic compounds in order to allow nutrition and growth. Blue-green algae thrive in warm weather and water that is stagnant, and despite the name, can also appear reddish brown or bright green in hue. According to Health Canada, 50 to 70 percent of blue-green algae instances release toxins that are harmful to humans and animals.

Blooms

• When blue-green algae spread or "bloom," thanks to optimal weather conditions, the algae can turn the water a greenish, bluish, reddish or brownish color, and create a scummy film on the surface area. Blue-green algae in bloom will often make the surrounding body of water smell like grass (in the case of newer blooms) or garbage (in the case of older blooms). However, understand that a lack of a smell does not mean the algae blooms aren't dangerous.

Toxicity

• Cyanobacteria blooms are made up of tiny cells. These cells can house various "cyanotoxins" or "cyanobacterial toxins." When cells break, the toxins are released into the water, and can be harmful to humans and animals. Unfortunately, few studies have been done on the toxicity of blue-green algae, so the number of toxins that can emerge from blooms remains unknown. Some of the most common are microcystins, a type of hepatotoxin, which can harm the liver; less common are neurotoxins, which can harm nervous systems. Other types of toxins discovered in blue-green algae include endotoxins and cytotoxins, which along with the other types of toxins, can irritate the skin.

Danger

• Coming into contact with the algae may cause skin irritation. Furthermore, because cyanobacteria can sometimes produce a set of "cyanotoxins," drinking algae-infested water could cause toxic poisoning, or respiratory irritation.

Symptoms

• Drinking cyanobacteria-tainted water or eating cyanobacteria-infested fish could result in headaches, stomach aches, fever, diarrhea, nausea or vomiting. Swimming in water that contains blue-green algae blooms, or any other contact with the water, could result in allergic reaction symptoms such as itchy eyes and irritated skin.

Treatment

• Rinse any scum off your body with water you know to be fresh. For particularly bad irritations, or if you feel ill after ingesting cyanobacteria, consult a physician.