Toxin-producing cyanobacteria found in water samples at Idaho’s Island Park Reservoir

By Christina Lords; Idaho Capital Sun

 This is an example of a blue-green algae bloom in Boyer Slough on Lake Pend Oreille in August 2021. (Courtesy of Idaho Fish and Game)

Idahoans should use caution when recreating in or near the Island Park Reservoir after high amounts of toxin-producing cyanobacteria was recently found in water samples there, according to a press release from the Idaho Department of Health and Welfare.

Visit the Idaho Recreational Water Health Advisories tab at the Get Healthy Idaho website for advisories and sampled locations at water bodies throughout Idaho.

The toxins can be harmful to people, pets and livestock.

The health department works closely with the Idaho Department of Environmental Quality to identify, respond to, and monitor cyanobacteria harmful algal blooms, known as cyanoHABs.

When recreating near or in Island Park Reservoir, take the following precautions while the advisory is in effect:

  • Avoid swimming, wading or other contact with the water. Take extra care to ensure children do not drink or get water on them.
  • Ensure pets and livestock do not drink or go into the water. If they have contact with the water, clean skin, hide or fur with clean water right away.
  • Do not drink or cook with the water. Boiling or filtering the water does not remove the toxins and can increase the risk of becoming sick.
  • Wash hands thoroughly in clean water after handling fish or objects from the water.
  • If you choose to eat fish from the water, clean and wash fish thoroughly in uncontaminated water. Filet the fish, and remove all fat, skin and internal organs before cooking. Cyanotoxins can build up in fish, and the risk to people is unknown.
  • Watch for symptoms. If you touch or swim in the water or inhale water droplets, you might experience a rash, hives, red eyes, wheezing, coughing or shortness of breath. If you swallow the water, you might have stomach pain, diarrhea or vomiting. You might have a headache, muscle weakness or dizziness. If your liver is damaged, your skin might turn yellow, and you will have dark urine. If you think you might be sick from cyanotoxin, consult your health care provider or call the poison center at 1-800-222-1222. In addition, notify
  • Monitor media reports and DHW’s website for health advisories.

Cyanobacteria are a natural part of Idaho’s water bodies, according to the health department. The amount of bacteria usually increases rapidly when the temperature of the water rises and there are nutrients for the bacteria to grow. The blooming can release toxic chemical compounds, called cyanotoxins, into the water.

Blooms don’t all look the same. They may look like mats, foam, spilled paint, or surface scum, and have a foul odor. Algal mats can be out of sight on the bottom of the water body.

Pets, livestock and wildlife can get sick or die within minutes to days after cyanotoxin exposure. Dogs can become sick first because they are more likely to swim in or drink contaminated water or lick contaminated water or bloom material from their fur.

If your pets or livestock have been in the water, immediately wash them with clean water to keep them from licking cyanobacteria off their bodies. Seek veterinary care immediately if your pets or livestock seem sick after going in or drinking the water.

For more information about cyanoHABs:

DEQ’s website at

DHW’s website at

The department will announce when the advisory has been lifted, according to the press release.

To view original article, please click here.