Illinois Urges Caution – Potential For Exposure To Toxins In Ohio River

Blue-Green Algae May Cause Harmful Algal Bloom

The Illinois Department of Public Health and the Illinois Environmental Protection Agency urge residents to use caution while in or on the Illinois portion of the Ohio River due to potential toxins from blue-green algae.  Blue-green algae (also known as cyanobacteria) are microscopic organisms that naturally occur in lakes and streams.  Rapid growth of algae is referred to as a “bloom.”

Both Illinois agencies have been working with the Ohio River Valley Water Sanitation Commission to respond to reports of a harmful algal bloom in the Ohio River.  The Commission and partners from various states along the Ohio River have been tracking an algal bloom in the river that stretches from West Virginia to the Illinois/Indiana border.  While a harmful algal bloom has not yet been confirmed in the Illinois portion of the Ohio River, river and weather conditions are favorable for such a bloom, particularly along shorelines.

Harmful algal blooms can produce toxic chemicals that cause sickness or other adverse health effects in people and pets depending on the amount and type of exposure.  The very young, the elderly, and people with compromised immune systems are most at risk.  Adverse health effects attributable to algal toxins can occur from direct skin contact, swallowing contaminated water, or inhaling water droplets in the air.  Symptoms of exposure to algal toxins include rashes, hives, diarrhea, vomiting, coughing, or wheezing.  More-severe symptoms may result from longer or greater amounts of exposure.

People who plan to be in or on the Illinois portion of the Ohio River are advised to be alert and to avoid contact with water that:

  • looks like spilled, green or blue-green paint
  • has surface scums, mats, or films
  • is discolored or has green-colored streaks 
  • has greenish globs suspended in the water below the surface

If you or your pet comes into contact with water you suspect may have a bloom of blue-green algae, rinse off with clean, fresh water as soon as possible.  Likewise, if you plan to eat fish you catch from water that has a bloom of blue-green algae, rinse all fish parts well in tap water before cooking and eating.  Activities near, but not in or on the river, such as camping, picnicking, biking, and hiking are not affected. With all activities, wash your hands before eating if you have had contact with river water or shore debris.

Illinois EPA has been working directly with the Illinois American Water Company-Cairo public water system, which uses water from the Ohio River, to ensure awareness of conditions and optimization of treatment.

If you are concerned you have symptoms that are a result of exposure to algal toxins, contact your health care provider or call the Illinois Poison Center at 1-800-222-1222.  If your pet experiences symptoms that may be a result of exposure, contact your veterinarian.

For additional information about harmful algal blooms, please visit