Blue-green algae toxin: People along Florida river breathed it in, but didn't pee it out

Research in 2018 found: People who are around toxic blue-green algae blooms breathe toxins into their bodies.

Brand-new research shows: Very few people who breathe in toxins urinate them out.

What's yet to be determined: How much of the breathed-in toxins gets into their blood.

Exposure to toxic blue-green algae can cause immediate symptoms such as a runny nose, watery eyes and trouble breathing. Long-term exposure has been linked to liver disease and suspected of causing neurological ailments years down the road.

But no one knows what concentration of the toxin and what length of exposure trigger health problems.

Related: If you're around an algae bloom, you're breathing in toxins, research shows

Researchers from Florida Atlantic University'sHarbor Branch Oceanographic Institute led by Adam Schaefer, an epidemiologist, studied 86 people who lived and worked around the St. Lucie River during the massive blue-green algae blooms in the summer of 2018 and found the toxin microcystin in all their noses.

Since then, Schaefer and scientists at the U.S. Centers for Disease Control and Prevention tested newly developed microcystin detecting methods and determined the toxin was in the urine of just three of the 86 people studied.

In the body or filtered out?

Does that mean the microcystin entered their bodies and stayed there? Or was the toxin filtered out by the hairs in the people's noses?

Unfortunately, there's no way to know because there's no method to determine how much microcystin is in the blood samples that were taken from the subjects.

"We don't have enough data or the methods to conclude what potential toxin is entering the body or staying in the body at this point in time," Schaefer said.

So the team that developed the test to find microcystin in urine is working on a microcystin blood test.

"We really need to look at all three pieces of the puzzle -- the nasal swabs, the urine samples and the blood samples," he said, "to get a complete picture of what's going in, what's coming out and what might be circulating around in people's bodies."

Schaefer couldn't say when the blood testing procedure will be available, "but I can say that it will be reliable. And that's the main thing."

Further testing

After testing the 86 people along the St. Lucie River, Schaefer and his colleagues took samples on the West Coast that October.

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"There weren't any active blooms there at the time," he said, "and none of the nasal swabs were positive for microcystin."

But subsequent research by research by a team from Yale and Florida Gulf Coast universities released in spring 2019 showed toxins produced by blue-green algae may be in the air pretty much everywhere and pretty much all the time.

The World Health Organization says "recreational contact" with water containing microcystin at 10 parts per billion is hazardous; the federal Environmental Protection Agency sets the threshold at 8 parts per billion.

But nobody has determined what level of microcystin in the air is hazardous to breathe, or how long you'd have to breathe it.

While he was being interviewed Friday, Schaefer was driving to Clewiston on the south shore of Lake Okeechobee to take more samples. There's no algae bloom in the area, but samples will help researchers "establish a baseline."

Researchers also will be able to look at subjects of the study in 10, 12 or more years to see if they suffer any long-term effects.

A study at Ohio State University that looked at statistics but not individual cases found people who live in areas with blue-green algae blooms are more likely to die from non-alcohol-related liver disease.

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Some scientists believe another toxin found in blue-green algae, BMAA, could lead to neurological ailments 20 or more years after exposure.

"Our objective is to do the best science we can," Schaefer said. "Hopefully our results can be used by a number of stakeholders in the area to improve conditions and improve human health."

How to help

Funding for direct human sampling for microcystin was supported by the FAU Foundation SpringBoard, a program that connects donors with projects that might otherwise go unnoticed.

For information:

Go to: fauf.fau.edu/springboard

Email: faufoundation@fau.edu

Call: 561-297-2891

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