State health officials: To know cyanobacteria is to avoid it
June 21, 2024 | By Lisa ScagliottiWith summer officially here and temperatures warming up Vermont’s ponds, lakes and streams, the Vermont Department of Health wants the public to be on the lookout for cyanobacteria as people look for safe swimming spots to cool off.
Cyanobacteria appears, green, blue-green or brownish-green on the water’s surface. Vermont Department of Health photo
Springtime brought heavy pollen accumulation to some bodies of water and now conditions are optimal for freshwater blooms of cyanobacteria (also known as blue-green algae).
Public health officials want you to know what these potentially hazardous blooms look like in order to avoid them.
Cyanobacteria are tiny microorganisms that are a natural part of freshwater ecosystems. Under certain conditions, they can multiply quickly, create blooms on the water’s surface and wash up along shorelines. Most important to know: They can produce toxins harmful to humans and animals.
Swimming or wading in water with a blue-green algae bloom may cause skin rashes, diarrhea, a sore throat, stomach problems, or more serious health issues.
“Exposure to cyanobacteria can harm your health. It can be especially dangerous to children who accidentally swallow the water when playing, and for pets that may drink from the shoreline or swallow the cyanobacteria when licking water off their coats,” said Bridget O’Brien, an environmental health scientist with the Department of Health.
Knowing what an algae bloom looks like
Cyanobacteria blooms are usually green or blue-green and can make the water look like pea soup or spilled paint, but they can be other colors and consistencies, too.
The Health Department has a webpage devoted to cyanobacteria with photos of what is and what is not blue-green algae along with a video online at HealthVermont.gov/Cyanobacteria.
The video sums up clues to look for in determining whether you see cyanobacteria.
“If you see anything that sticks to rocks, plants, or the bottom of the lake, or if you can pick it up with a stick, it’s NOT cyanobacteria,” the narrator says. “If you can see that it has separate leaves, it’s not cyanobacteria either. It may be duckweed or another plant with small leaves that can look like cyanobacteria from a distance.”
Also, if what you see is yellowish and both on the ground and on the water in late spring and early summer, it’s most likely pollen.
So what are the characteristics of cyanobacteria? “Typically they look like small pinhead-sized particles” on the water’s surface, the video explains. “It can can look like pea soup or a blue-green paint spill on the water’s surface water.” It also can appear as murky water that’s “a brownish-green, milky green, or blue.”
Examples of cyanobacteria - photos courtesy Vt. Health Department
Examples of what is NOT cyanobacteria - Vt. Health Dept. photos
Also online is the Health Department’s Cyanobacteria Tracker where people can check reported conditions along Lake Champlain and various inland lakes in Vermont. The map shows where cyanobacteria blooms have been reported recently, but given how rapidly algae blooms can appear, it can't tell you what the conditions are currently at your favorite swimming area.
To help the tracker collect and share up-to-date information, people can report and upload photos of suspected cyanobacteria blooms using the Tracker’s online form. Experts from the Departments of Health and Environmental Conservation and the Lake Champlain Committee review the reports and those they confirm are posted on the Cyanobacteria Tracker.
“It’s important to know what you are literally getting into,” O’Brien said. “Cyanobacteria blooms thrive in warm water, and as water temperatures rise, there will be more blooms showing up on lakes, ponds and beaches. If the water looks discolored, or even if you’re not sure if it’s a bloom – play it safe and find a different spot,” she said.
Health officials stress that bloom conditions can and do change quickly, and not all locations are monitored daily. Vermonters should learn what blooms commonly look like, and always pay attention to any posted warning and closure signs. People should also check with their town officials for conditions at locally managed beaches.
What to do if you see an algae bloom
If you come upon an algae bloom at a lake or pond, here are recommendations from the Health Department:
Avoid contact with the water.
Do not let pets or livestock swim in or drink the water.
Contact the beach manager or municipal offices where you saw the algae and email the Department of Health at bloomalert@Vermont.gov
If you come in contact with cyanobacteria, rinse off thoroughly as soon as possible.
Talk with your health care provider if you have concerns about possible exposure.
More information
Here are several links to websites to learn more about cyanobacteria and how to stay safe in the water:
Lake Champlain Committee which has a program of volunteer cyanobacteria monitors. To get involved, email lcc@lakechamplaincommittee.org.