The Louisiana Department of Health (LDH) is urging residents and visitors to avoid areas of Henderson Lake where a cyanobacteria, or blue-green algae, bloom has been observed.
The presence of a cyanobacteria bloom in Henderson Lake has been confirmed with satellite imagery. While some algae are harmless, certain types of cyanobacteria can produce toxins that are harmful to people and animals, according to LDH. Testing is required to determine whether toxins are present.
Because algal blooms can move and change quickly, LDH recommends avoiding areas where a bloom is visible or suspected. You cannot tell whether a bloom is producing toxins just by looking at it.
"Louisiana's lakes and waterways are an important part of how we live, work, and spend time outdoors, and a few simple precautions can help people enjoy them safely," said LDH Secretary Bruce D. Greenstein. "If you see or smell an algal bloom, stay out of the affected water and keep children and pets away. When you're unsure, please avoid all contact with the water."
What to look for
An algal bloom is a rapid growth of algae on the surface of the water. Blooms may appear blue, bright green, brown, or red and can have a strong odor similar to rotting plants. Foam or scum may also form on the water's surface.
Cyanobacteria are a common cause of harmful algal blooms in freshwater lakes and rivers. Blue-green algae thrive in warm, calm, sunny conditions and water temperatures above 75°F. Blooms are more likely during the summer and fall but can occur at any time of year.
If you see or smell an algal bloom
- Stay out of affected water. Avoid swimming, wading, boating or other recreational activities in areas with an active bloom.
- Keep pets away. Do not allow pets to swim in or drink water where a bloom is present.
- Wash after contact. If you or your pet comes into contact with affected water, promptly wash with soap and clean water.
- Do not drink or cook with affected water. Do not use water from an area experiencing an algal bloom for drinking, cooking, or preparing food.
- Watch for symptoms. Exposure to harmful algal toxins can cause rashes, stomach cramps, coughing, nausea, diarrhea, or vomiting. High levels of exposure can affect the liver and nervous system. Contact a health care provider if you develop symptoms after exposure.
LDH encourages residents to be aware of the signs of a bloom and avoid contact with affected water. For health questions or concerns, call LDH's Section of Environmental Epidemiology and Toxicology (SEET) at 888-293-7020.
