Northern Kentucky University:
Ohio Sea Grant Fact Sheet:
Ohio Algae Information for Recreational Waters
The information below is found on the Ohio Environmental Protection Agency website.
What is a harmful algal bloom?
A harmful algal bloom (HAB) is a large growth of bacteria that can produce toxins. These toxins may affect the liver, nervous system and/or skin.
What causes HABs to form?
Some factors that can contribute to HABs include sunlight; low-water or low-flow conditions; calm water; warmer temperatures; and excess nutrients (phosphorus or nitrogen). The primary sources of nutrient pollution are runoff of fertilizers, animal manure, sewage treatment plant discharges, storm water runoff, car and power plant emissions and failing septic tanks. The State of Ohio is currently working on a statewide nutrient reduction strategy that will document ongoing nutrient reduction activities and identify areas where more work is needed.
How dangerous are HABs?
If you touch HABs, swallow water with HAB toxins or breathe in water droplets, you could get a rash, have an allergic reaction, get a stomach ache, or feel dizzy or light-headed. HABs also are toxic to pets.
Always look for HABs before going in the water. Check for HAB advisories. Ask the park manager if there has been a recent HAB because colorless toxins can still be in water.
How will I know if there is a HAB?
HABs have different colors and looks. Some colors are green, blue-green, brown, black, white, purple, red and black. They can look like film, crust or puff balls at the surface. They also may look like grass clippings or dots in the water. Some HABs look like spilled paint, pea soup, foam, wool, streaks or green cottage cheese curd. Click here for images of HABs.
What should I do if I see a HAB?
Stay out of water that may have a HAB.
Do not let your children or pets play in HAB debris on the shore.
After swimming or wading in lake water, even where no HABs are visible, rinse off with fresh water as soon as possible.
Never swallow any lake or river water, whether you see HABs or not.
Do not let pets lick HAB material from their fur or eat HAB material.
Do not drink or cook with lake water.
See a doctor if you or your children might be ill from HAB toxins. If your pet appears ill, contact your veterinarian.
What about fishing and other activities?
If you plan to eat the fish you catch, remove the guts and liver, and rinse fillets in tap water before eating. Other activities near the water such as camping, picnicking, biking and hiking are safe. If you are picnicking, wash your hands before eating if you have had contact with lake water or shore debris.
Public Interest Center, Ohio EPA