Toxic Blue-Green Algae and Nutrient Pollution

Toxic blue green algae is becoming and increasingly burdensome and dangerous problem in many waterbodies of the Umpqua Basin. In 2010, a dog died within one hour after drinking water at Lawson Bar on the South Umpqua River. The year before, two other pets died quickly near Elkton. In 2007, 21 Sea Otters were found dead off the coast of California. In each of these cases, the animals died from ingesting toxins released from microcystis, or blue-green algae. These colorless and odorless toxins pose serious health risk to animals and humans, especially young children. However, by knowing the signs and staying alert you can reduce your risk of exposure and protect your family.

These toxins, if consumed in high enough quantities, can lead to muscle cramps, twitching, and in extreme cases paralysis, cardiac or respiratory failure, and death. Another variety of toxin can affect liver function and induce nausea, vomiting, diarrhea and, in extreme cases, even acute liver failure.

Know the Signs

There are many different varieties of Blue-Green algae that produce toxins in lakes, streams, rivers, and other bodies of water. Avoid contact with water that appears scummy or discolored. Blue-Green algae has often been reported to look like oil on the surface of the water, brightly colored green or blue paint, as well as other colors and forms. Since there is no accurate way to determine visually if an algae bloom is toxic, avoid contact if you see any of these signs. 

One of the most significant and visible warning signs occurs after contact with contaminated water. Exposure to cyanobacteria can be serious and result in a range of symptoms including skin rash, diarrhea, cramps, vomiting, numbness, dizziness and fainting. If you experience any of the signs and symptoms seek medical help immediately and avoid contact with the water body.

The State of Oregon and other government and non-profit organizations are posting informational warning signs at recreational areas. Be especially aware when signs state a health advisory is in effect for the known presence of toxic blue-green algae blooms. These indicate that toxins have been detected in the immediate water body. Avoid all contact with the water and keep you pets and children away.


Toxins are released as the algae dies and their cells burst. Therefore, toxins can be present in the water at extremely high concentrations with no visual signs of an algae bloom. If a health advisory is in effect do not enter the water.

Drinking Water

When camping you should be extremely careful where you draw your water source from. Personal filtration devices such as charcoal filters, backpacking filters, and UV pens will not remove toxins from blue-green algae. Remember the toxins are invisible, filtering out the visible algae will not eliminate the toxins. Boiling water will also not remove the toxins and could release more toxins into the water by bursting algal cells. 

Learn More

Current Health Advisories

More Information

Report Dog Death or Possible Algae Sighting

Report Water Quality Concerns