MPCA: Toxic blue-green algae may already be in Minn. lakes

A harmful blue-green algae bloom. Photo courtesy of the Minnesota Department of Health. 

The Minnesota Pollution Control Agency and the Minnesota Department of Health are advising people and pets to stay out of lakes with possible blue-green algae over Memorial Day weekend. Mild spring weather has created ideal conditions for toxic algae blooms this year, according to officials.

Blue-green algae blooms typically begin to form in June, but due to the mild weather this year, MPCA officials believe the algae may already be present in some Minnesota lakes. Harmful blooms often look like pea soup, green paint or floating mats of scum and are often accompanied by a bad smell.

Swimming, boating, water skiing or bathing in water with blue-green algae or a recent bloom can make people sick. According to the MDH, dogs are at particular risk because they tend to swallow more water than humans while swimming and often lick their coats after leaving the water.

Last summer, authorities investigated two human illnesses and several dog deaths following exposure to blue-green algae in Minnesota lakes. 

People exposed to blue-green algae can experience symptoms such as vomiting, diarrhea, rash, eye irritation, cough, sore throat and headache.  Dogs can experience vomiting, diarrhea, rash, difficulty breathing, general weakness, liver failure and seizures. Owners should seek veterinary care immediately if their dog experiences any of these symptoms after swimming in a lake.

Tips to protect yourself and your pets

Not all blue-green algae is dangerous, but officials say you cannot tell if a bloom is harmful just by looking at it. Before you or your pets enter the water, check the lake for algae in the water or along the shore. Harmful blooms are not always large and dense and can sometimes cover small portions of the lake with little visible algae present.

“If [a lake] looks bad and smells bad, don’t take a chance,” Pam Anderson, MPCA water quality monitoring supervisor, said in a statement. “We usually tell people: if in doubt, stay out.”

If you or your pet comes in contact with blue-green algae, use fresh water to rinse it off immediately.