LAKE ERIE — Tom Bridgeman, an ecology professor and director of the University of Toledo’s Lake Erie Center, poured a bright green sample of Lake Erie water into a bottle, his hands steady despite the heavy rocking of the waves beneath the university’s research boat.
The bottle contained a concentrated collection of bright blue-green algae, the kind of sample researchers have collected countless times in the decades-long fight to understand, measure and prevent the now-annual harmful algae blooms on western Lake Erie.
Humming in the background was something more novel: a small pump zip-tied to the side of the boat collecting particles hanging in the air.
Scientists from the University of Toledo and the University of Michigan are coordinating studies to understand more about how harmful algae bloom toxins become airborne, how far those toxins travel and what they do when they reach people’s lungs. They hope to develop a model that could predict when blooms will cause air quality dangers and warn people to stay off the water or close their windows.
It’s a worthy effort, said David Kennedy, a University of Toledo medicine professor and co-director of the Women and Philanthropy Genetic Analysis Center. Early indications from his lab work show exposure to airborne toxins from Lake Erie’s harmful algae blooms could harm people with asthma and other health conditions. Other researchers have shown a possible link between neurotoxins and Alzheimer’s and ALS, a neurodegenerative disease.
It’s easier to tell people to avoid scummy water than to tell them to avoid the outdoor air.
“To some extent, you can control what you’re drinking. You drink 2 liters a day, hopefully, and you can hopefully obtain clean drinking water,” Kennedy said. “You breathe 11,000 liters a day. Just the sheer volume that your lungs are handling relative to what you drink and ingest is orders of magnitude higher.”
“And then the lungs are really good at exchanging things quickly and getting them into your bloodstream. With all that together, we were like, ‘This seems like it really was not well-explored.’”
Scientists and doctors have long warned people against touching or drinking bright-green scum growing in western Lake Erie or other water bodies, especially warm, shallow ones near farmland. The scum indicates a harmful algae bloom, which happens when algae grow out of control and produce toxins that can harm people and animals.
But when Lake Erie charter boat captains started complaining of an “August cough” they would develop each late season and emergency room data showed people who had encountered harmful algae blooms developed respiratory issues, scientists started asking whether the toxins may degrade the air as well as the water.
“That’s when we really started to look and say, ‘Is the lung a target?’” Kennedy said. “And that really made a lot of sense.”
Harmful algae blooms increasing in Michigan
Harmful algae blooms have become an annual summer phenomenon on western Lake Erie, a relatively warm and shallow water body that is loaded with nutrients that run off farmland surrounding the Maumee River and River Raisin. The western Lake Erie bloom is caused by a bacterium called cyanobacteria, known as “blue-green” algae, even though it is not a true algae.
Captain Don McGee, owner of King and Eye Charters, gets a cough when algae concentrations are high, cyanobacteria or not. He already deals with allergies and pulmonary problems, and additional particles in the air make his symptoms worse.
“It’s not going to knock you down, but I do get a cough,” McGee said.
McGee, 71, and other charter boat captains have partnered with The Ohio State University’s Stone Laboratory to help collect water samples while they are out on Lake Erie. Their work helps scientists understand a broader picture of water quality in the lake.
Water quality matters greatly to charter captains and the economy surrounding the lake’s popular sport fishery, McGee said.
“If we have a cyanobacteria algal bloom, I will be getting phone calls one after another telling me they’re not coming. They’re not going to subject themselves,” he said. “(People ask), What’s it going to do to me?”
Harmful algae blooms are increasingly being confirmed on Michigan’s inland waters. As of Aug. 11, the Michigan Department of Health and Human Services had confirmed blooms had taken place on 47 water bodies in Michigan, including Proud and Pontiac lakes in Oakland County. The health department and Michigan Department of Environment, Great Lakes and Energy collect reports of blooms and then take samples to confirm them.
Confirmations are on the rise since 2016, according to data provided by the state, increasing from 21 a decade ago to 75 in 2025. But officials said increased awareness of algae blooms might contribute to the trend.
Breathing in bloom toxins poses danger
The dangers of harmful algae bloom toxins hit the international scene in the 1990s after the deaths of dozens of patients of a dialysis clinic in northern Brazil, Kennedy said. Their deaths, and as many illnesses, were caused by exposure to cyanotoxins from water that came from a nearby lake that was experiencing a harmful algae bloom.
“People started paying attention,” Kennedy said.
More examples of the dangers of encountering cyanotoxins arose in the Toledo area about a decade ago. In 2014, a 7-year-old girl was hospitalized and intubated because of breathing issues that started immediately after swimming in western Lake Erie’s Maumee Bay, where a harmful algae bloom was releasing cyanotoxins.
The next year, a 14-year-old was hospitalized in the pediatric intensive care unit after encountering cyanotoxins during a harmful algae bloom in Maumee Bay. She was experiencing a fever, rash, vomiting, diarrhea and dehydration. In 2016, a 16-year-old went to the hospital complaining of lesions, a headache, rash and fevers after she encountered cyanotoxins while swimming in the Maumee River two weeks before.
Kennedy and his colleagues tracked the three cases in a 2023 paper. While all of the patients recovered, the doctors argued the options for diagnosing and treating cyanobacteria exposure are “lacking,” which makes it very important for health care providers to monitor for and track exposures.
Researchers now are investigating what happens when people encounter even lower doses of the toxin carried by air.
“Beyond the acute effects, are there chronic, long-term effects from low-dose, chronic exposure?” Kennedy said. “Are there conditions that may make you more susceptible to that?”
Predicting airborne blooms
About five years ago, University of Michigan chemistry professor Andrew Ault discovered cyanobacteria toxins can become airborne when agitated by wind and waves.
A sprawling research effort has followed. Scientists at UM and the University of Toledo are trying to answer important questions about what happens when harmful algae bloom toxins get into the air — how many toxin particles actually get into the air, how far can they move and what happens when they reach a person’s lungs?
Allison Steiner, professor and chair of UM’s climate and space sciences and engineering department, is working with Ault and the University of Toledo researchers to understand how far the toxins travel when they reach the air and what concentrations they hit along the way. She hopes to use the information to build models that could predict when and where harmful algae blooms could cause breathing problems.
“It could be a health tool,” Steiner said. “For people who live in coastal areas, it might be that high bloom days … that might be a day when you want to be inside, or maybe that’s a day when boaters shouldn’t go out. We can use wind patterns to see who might be exposed.”
Kennedy, the University of Toledo medicine professor, is working with his lab to understand how people’s bodies react when they are exposed to different levels of airborne cyanobacteria toxins. They want to see whether some health conditions might make people more susceptible to problems.
Signs are pointing to yes. Through preliminary experiments with mice and biopsied human cell tissue, they can see the airborne toxins harm some patients more than others. Cells from asthmatic donors respond more strongly to toxins, for example, Kennedy said.
The air sampling device attached to the University of Toledo boat will show what level of airborne toxins boaters would be exposed to if they’re on the water during a day when the harmful algae bloom is active.
Kennedy’s lab also has air quality monitors in Toledo and nearby, including one outside the university’s Lake Erie Center in Oregon, Ohio.
“That filter, it comes out green sometimes,” said Bridgeman, director of the Lake Erie Center.
By measuring toxins in the actual air around western Lake Erie, Kennedy can mimic the same levels of toxins in his lab experiments that people in Toledo and those boating on Lake Erie actually breathe.
“From the public health perspective, we want to know who may be at risk and what are risk categories,” Kennedy said. “We’re going to have to collect a lot of data over a long period of time because seasons are different, weather conditions vary. Every day is sort of like a new data point, and we have to put a lot of those data points together.”