An algal bloom in Lake Diane was tested for cyanotoxins. Courtesy | Facebook

An algal bloom in Lake Diane in southern Hillsdale County is currently free of cyanotoxins, which can cause illness and in rare cases death, but the lake will still be monitored.

A recent lab test revealed that samples taken from the lake on Aug. 15 did not contain the harmful chemicals sometimes produced by the cyanobacteria that are found in algal blooms.

According to Paul Andriacchi, environmental health director of the Branch-Hillsdale-St. Joseph Community Health Agency, a resident living by the lake spotted the algal bloom and reported it to Michigan Department of Environment, Great Lakes, and Energy.

Kevin Mack, board member of the Lake Diane Community Association, said the algal bloom is located on the northeast side of the lake in a small area called the North Bay. According to Mack, the bay is a “dead end channel,” so the algal bloom is contained in a small area and does not pose a threat to the rest of the lake.

Around the same time the algal bloom was reported to EGLE, a resident living on the northeast side of the lake was harmed by the algal.

“She came into contact with it, and she got some sort of rash from it,” Mack said.

With regard to the incident, Alexandra Rafalski, a toxicologist at the Division of Environmental Health at the Michigan Department of Health and Human Services, said cyanotoxins are not the only cause of a rash. That is because there are other components of cyanobacteria that are yet to be completely understood.

Andriacchi said he communicated with Lake Diane Community Association, suggesting they place signs on the docks alerting residents and visitors of the algal bloom.

“We still advise people to stay away from them,” Andriacchi said.

Harmful algal blooms, or HABs, often appear as sheets of colored scum on the surface of the water, or an abundance of floating algae. HABs are caused by a rapid growth of toxin-producing cyanobacteria in the water. Cyanotoxins are harmful to pets, humans, and the environment.

If an algal bloom is toxic, “any human or animal contact could be dangerous,” Andriacchi said.

Ingesting water with cyanotoxins may cause runny nose, itchy eyes, difficulty breathing, diarrhea or vomiting. Skin contact with cyanotoxins may cause rashes, blisters, or hives.

Cyanobacteria also have the ability to turn their toxins on and off, so EGLE still advises people to avoid contact with bodies of water that have non-toxic algal blooms.

“If the bloom is reported again, we could assume the toxins could be present,” said Rafalski.

In 2021, Michigan reported 77 harmful algal bloom events, which were associated with five human illnesses and five animal illnesses, according to the Centers for Disease Control and Prevention.

Mack said the association plans to keep an eye on the algal bloom and report any concerning changes in the algal bloom to EGLE and post an update on their Facebook page.

“We would probably try to educate the community,” Mack said.