Harmful Algal Blooms: When in doubt, stay out!

Central District Health and the Idaho Department of Environmental Quality issued the first harmful algal bloom health advisory of the summer season on June 23 because of cyanobacterial blooms in Little Camas Reservoir. Most of the year, Idaho’s lakes and reservoirs are safe to enjoy. But when water temperatures increase and the right type of nutrients are available, some bodies of water can produce harmful algal blooms, which can be dangerous for humans, pets, livestock, and wildlife.

What is a harmful algal bloom?

They are bacteria (not algae) that can produce toxins. The blooms are also referred to as cyanobacterial blooms. When weather conditions are calm and there is an increase in water temperature and nutrients, they can rapidly increase in number and produce a bloom. Blooms can occur at any time, but they most often occur in late summer or early fall.

What do these blooms look like?

Harmful blooms can be blue, bright green, brown, or red and may look like paint or anti-freeze floating on the water. As the bloom matures, it may look like foam, scum, or mats on the surface of freshwater lakes and ponds. If you or pets or livestock swim in or drink from water that contains a bloom, the effects can be dangerous.

What are the symptoms of an exposure to a bloom?

The most common effects are skin and eye irritation. Other more severe effects can include:

  • Difficulty breathing
  • Stomach pain
  • Nausea
  • Vomiting
  • Diarrhea
  • Dizziness
  • Numbness and tingling in lips, fingers, and toes

If you experience mild irritation, rinse with clean water immediately. If you experience severe symptoms, you should seek medical attention.

Are the symptoms the same for animals?

Pets and livestock exposed to dangerous blooms may exhibit symptoms and conditions such as:

  • Weakness
  • Staggering
  • Foaming at the mouth
  • Difficulty breathing
  • Convulsions/seizures

If your pet comes in contact with a bloom, rinse them well with clean, fresh water immediately. If symptoms occur, call a veterinarian. In severe cases, animals may die within minutes and up to several hours after they have been exposed to harmful algal blooms. When the blooms decompose, they can also kill fish that live in the water.

How can a person reduce the risk of exposure?

  • Do not go in or near water that has an unusual color, and keep children, pets, and livestock out of the water.
  • Avoid any water sports such as swimming, diving, water skiing, or boating in areas with harmful algal blooms.
  • Do not use untreated water for drinking, bathing, cleaning, or cooking. Boiling water that has been contaminated by a bloom will not remove toxins, and it may actually cause more toxins to be released.
  • Remember: “When in doubt, stay out.”



(Editor’s Note: A Closer Look at Your Health airs most Tuesday mornings on KBOI News Radio 670. This is an edited transcript of the July 3 segment.) 

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