Blue-Green Algae Can Be A Health Hazard

blue gree algaeWhen in doubt, best keep out! Lincoln County Health Officials are reminding people to watch out for blue-green algae blooms in waterways this summer and to avoid swimming in water where visible scum or mats of blue-green algae are present. Lincoln County Health Department reports blue-green algae on some of our lakes in Lincoln County already this year.

Blue-green algae, technically known as cyanobacteria or what many people refer to as “pond scum,” are naturally found in waterways in Wisconsin at low levels. When conditions are just right blue-green algae can grow very quickly in number, producing a scum layer or mat on the surface of water. Blooms typically occur during the warm weather months between mid-June and mid-September. People may be exposed to blue-green algae through contact with the skin, inhalation, or by swallowing contaminated water.

Exposure to algae blooms may cause you to have the following symptoms: sore throat, congestion, cough, wheezing, difficulty breathing, eye irritation, itchy skin, red skin, hives, earache, headache, abdominal pain, diarrhea, and vomiting.

Animals can also become ill from blue-green algae blooms. Animals that have been exposed may show any of the following symptoms: lethargy, difficulty breathing, diarrhea, seizures, weakness and vomiting. To protect pets from algae blooms do not let animals drink lake water during algae blooms. Keep animals out of green water or where you see foam, scum or mats of algae; and rinse animals off immediately if they are exposed to algae. Do not let them lick the algae from their fur.

Since it is very difficult to tell whether algae blooms are toxic without lab analysis of the water; the safest thing to do is to treat every algae bloom as if it could be dangerous.

Measures to protect you, family, and animals from harmful algae blooms:

  • Do not swim in water that looks like “pea soup”, green or blue paint or that has a scum layer or puffy blobs floating on the surface.
  • Do not boat, water ski, etc. over such water.
  • Do not let children play with scum layers, even from shore.
  • Shower and wash hands after swimming in lakes, rivers and ponds.
  • Do not fish from lakes where algae scum is present.
  • Do get medical treatment right away if you think you, your pet or livestock might have been poisoned from algae toxins.
  • Do pay attention and respect water body closures and health advisories.

For more information regarding blue-green algae blooms contact Meghan Williams, Lincoln County Health Department, at 715-536-0307 or visit the Wisconsin Department of Health Services website: or the Wisconsin Department of Natural Resource’s website:

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