Watch Out For Blue-Green Algae Blooms

Aug 7, 2014

Earlier this week a widespread bloom of blue-green algae prompted a warning for hundreds of thousands of people in Toledo, Ohio. Health officials said the algae found in Lake Erie made drinking water from the lake unsafe.

The same bacteria creating those health risks are present in Vermont’s lakes and streams. Officials stress that the intakes for drinking water in Lake Champlain are deep and the algae blooms you may see on the big lake tend to be on the surface. While that may be good news for potable water, there are other potential health problems associated with blue-green algae, and state officials say recreational lake users should keep an eye out for it.

"Often blue-green algae looks like a thick pea soup. It doesn't have stringy parts or leaves." - Sarah Vose, Vermont Department of Health

Cyanobacteria is a bacteria that has a blue-green color, said Sarah Vose, state toxicologist for the Vermont Department of Health. Officials encourage people to avoid contact with any water with a cyanobacteria bloom. People who come in contact with blooms can have skin rashes and some irritation. If it’s ingested it can cause sickness.  

“Some blue-green algae create toxins in their cells, and if those toxins are released and get inside a person’s body, those could also cause adverse health effects,” Vose explained. It’s also a danger for animals. “Dogs are often more likely to drink more of the water and come into contact more frequently with the blue-green algae blooms than people are.”

Blue-green algae blooms, like this 2012 one in Addison County, look like thick pea soup or green paint. There are no leaves or stringy filaments.
Blue-green algae blooms, like this 2012 one in Addison County, look like thick pea soup or green paint. There are no leaves or stringy filaments.
Credit Vermont Department of Health

The Health Department has pictures on their website that can help people identify blue-green algae. “Often blue-green algae looks like a thick pea soup. It doesn’t have stringy parts or leaves to it. That could be a different type of algae and we also have trained volunteer monitors throughout the state who are working very hard to give us visual observations of conditions on the lake. The Vermont Health Department and the Lake Champlain Committee, the Lake Champlain Basin Program and the Department of Environmental Conservation are all of the monitoring partners who are out looking at conditions on the lake.” If a bloom is spotted people should avoid that water, and can contact the Health Department to report it.

Right now, there are two areas on high alert: St. Albans Bay and Missisquoi Bay.

St. Albans Bay is on high alert for blue-green algae blooms this summer.
St. Albans Bay is on high alert for blue-green algae blooms this summer.
Credit Vermont Department of Health

“Blue-green algae are a naturally occurring part of our ecosystem, so they are found in many different parts of our lake. There are some specific parts of Lake Champlain that seem to be more susceptible to blooms every year. The types of nutrients in the water and the temperature of the water, those are the two biggest factors that determine when the bloom will be present.” Vose said the cyanobacteria multiply and form blooms when those conditions are right.

Once a bloom is present it could stick around for a number of days if the conditions remain favorable, but mostly they are washed away with rainstorms, sometimes within a few hours. Not all blooms form the dangerous toxins, but they should be avoided.

“As long as people use their common sense and not coming into contact with water that has an obvious blue green-algae bloom, the risk is very low,” Vose said.