Blue Green Algea

What is Blue-green Algae Toxicity?

What we commonly call blue-green algae are actually photosynthetic bacteria, known as cyanobacteria, which live in water. These types of bacteria are found worldwide and are among the oldest and largest groups of bacteria.

The bacteria are normally present in the water. Problems occur when very exuberant growth occurs forming what is termed an algal bloom. The algae numbers increase dramatically, and the bacteria tend to rise to the surface, often forming a mat that can be several inches thick, especially near shore.

The blooms usually form in slow moving or stagnant waters rich in nutrients. Most commonly, the blooms occur in the late summer or early fall, but can occur at any time. The blooms can look like foam, scum or mats that can be blue, green, brown or red. Some blooms may not affect the appearance of the water.

The cyanobacteria can cause problems in many ways. The blooms can block out the sunlight to the water and use up all the oxygen killing other plants and animals. They can produce toxins that are among the most powerful natural toxins known. There are many different types of toxins produced; including neurotoxins, liver toxins, kidney toxins, and tumor promoters. No antidotes have been identified for these toxins.

People and animals are exposed to these toxins when drinking water from, playing in, or inhaling aerosols from a contaminated body of water. Some toxins will cause skin irritation. If inhaled, some can cause allergy or asthma-like symptoms. Swallowing water can also cause severe gastroenteritis, including vomiting and diarrhea. Additionally, some bacteria, such as Clostridium botulinum (botulism), can use these blooms as a growth medium.

Treatment for blue-green algae toxicity revolves around decontamination, symptomatic and supportive care.

The best ways to protect yourself and your animals is to avoid areas of water where you see foam, scum, or mats of algae on the water. If you or your animals do swim in those areas, make sure to rinse off immediately with fresh water. Do not irrigate with pond water that looks scummy or smells bad. If you think you or your animal has been poisoned by blue-green algae, seek medical attention immediately!

More information on cyanobacteria can be found at www.cdc.gov.

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