Harmful algae prompts swimming advisory for parts of Lake Anna

LOUISA COUNTY, Va. -- Virginia health officials are warning folks not to swim in a section of Lake Anna in Lousia County because of the dangers of harmful algae.

The swimming advisory issued by the Virginia Department of Health (VDH) Friday impacts the upper waters of the North Anna arm, including the “Sandbar” of the lake, and downstream to the Route 522 Bridge.

"Results of samples collected 6/17/24 contained cyanobacteria concentrations that pose a public health concern," VDH officials wrote. "Microcystin, a cyanotoxin, was detectable but below levels which pose a health risk. Three other cyanotoxins were below detectable levels." [ Click here to read more. ]

Cyanobacteria can cause skin rash as well as gastrointestinal illnesses, like upset stomach, nausea, vomiting, and diarrhea, according to officials.

"Weather and other environmental factors can cause rapid changes in water quality," officials noted. "Be aware of algae blooms and avoid water that smells, is discolored, or where there are dead fish present."

The public was urged to avoid that specific area of the lake until algae concentrations return to acceptable levels, VDH officials said.

"People and pets are advised to avoid swimming, windsurfing, and stand-up-paddle-boarding, as well as other activities that pose a risk of ingesting water. Activities such as boating may continue with proper precaution in advisory areas," officials wrote.

The latest advisory marks the seventh straight year with harmful blooms in the man-made lake that cools Dominion Energy’s North Anna nuclear power plant.

INTERACTIVE: Click here for VDH's Harmful Algal Bloom Map

Additional monitoring on the lake is planned for the week of July 15, officials said.

Health officials said that for the advisories to be lifted, two acceptable samples would need to be collected at least 10 days apart.

Health officials urged folks to take the following precautions to prevent illness:

• Avoid contact with any area of the lake where water is green or an advisory sign is posted, WHEN IN DOUBT, STAY OUT!
• Not allow children or pets to drink from natural bodies of water.
• Keep children and pets out of the areas experiencing a harmful algae bloom and quickly wash them off with plenty of fresh, clean water after coming into contact with algae scum or bloom water.
• Seek medical/veterinarian care if you or your animals experience symptoms after swimming in or near an algal bloom.
• Properly clean fish by removing skin and discarding all internal organs; cook fish to the proper temperature to ensure fish fillets are safe to eat.

Anyone who has come in contact with the bloom or has experienced health-related effects following exposure to a bloom is asked to call the state's Harmful Algal Bloom Hotline at 1-888-238-6154. Visit SwimHealthyVA.com for more information.