Research Shows Harmful Algal Blooms Can Become Airborne

Waves lapping against the shoreline is always a pretty scene, but it may also be a way for toxins from harmful algal blooms to become airborne.

By Morgan Sherburne

Harmful algal blooms — blooms composed of blue-green algae — crop up throughout the Great Lakes region during hot summers. Algae reproduces, unchecked, producing toxins and sapping oxygen from water. These blooms occur naturally, but agricultural run-off provides nutrients for the algae to thrive.

Bloom, Representative image, source: Flickr Labeled for reuse
Photo Credit: Dr. Jennifer L. Graham | U.S. Geological Survey

This is the case in Lake Erie, where agricultural runoff contributes to massive annual blue-green algal blooms. A bloom in 2014 caused Toledo to shut down the city's drinking water supply from the lake for three days.

According to the Environmental Protection Agency, toxins produced by the algae can cause rashes, liver illness, vomiting, diarrhea, neurological effects, respiratory problems and even death.

Now, University of Michigan researchers Andrew Ault and Kerri Pratt are wondering whether toxins from these kinds of algal blooms can be transmitted by air when waves break against the shoreline.

"These tiny aerosol particles, similar to those produced from an aerosol spray can, are about one hundred times smaller than a human hair," said Pratt, assistant professor of chemistry, and earth and environmental sciences.

Ault and Pratt have established the first answer to that question. Their study published in Environmental Science & Technology shows that biological material from algal blooms can become ejected into the air.

"Harmful algal blooms have been expanding as an important issue we're dealing with, particularly for the Great Lakes," said Ault, assistant professor of environmental health sciences, and chemistry.

"We've realized that not only are these important for water quality issues, but that you also generate atmospheric pollutants from these harmful algal blooms. We're the first to show that wave-breaking of these blooms can release material into the atmosphere, which can have impacts on people breathing it in."

In 2014, Pratt's and Ault's research teams, funded by the U-M Water Center, began taking water samples from Lake Erie and Lake Michigan. In September, they sampled Lake Erie water in the Maumee Bay near Oregon, Ohio, and in Catawba Island State Park near Port Clinton, Ohio. In October 2014, they sampled water from Lake Michigan near Michigan City, Ind.

Next, lead graduate student Nathaniel May re-created wave action in the lab using their lake spray aerosol generator. Taking air samples from the generator, the researchers were able to show that biological material from harmful algal blooms did become aerosolized.

"We found that when we had higher blue-green algae concentrations in water, we saw more aerosol particles that contained markers of biological content," Pratt said.

Ault's and Pratt's research has shown that particles of this size can be carried hundreds to thousands of miles by air, and wind speeds as little as 7 miles per hour can create lake spray aerosols.

"Our hypothesis is that toxins from this blue-green algae might be getting into the air, in which case, people might be subjected to inhalation exposure, serving as a previously unrecognized health risk beyond drinking water contamination," Pratt said.

Next, Ault plans to test specifically for toxins in the aerosols and how far they can be transported inland from the lakes.

Source: University of Michigan

Read the full study:  Aerosol Emissions from Great Lakes Harmful Algal Blooms

Media

Taxonomy

• Public Health
• Decontamination
• Contaminant Removal
• Water Quality
• Algae
• Contaminant Movement Mapping
• Lake Management
• Water Quality Research

4 Comments

1. How could we best caution public with signage, around HABs? It does not seem as easy as you might at first think. The blooms could often not even put out much toxin content, nor affect a whole lake. Any resort business on that lake could be adversely affected needlessly.... or, be gravely affected if toxins did harm people and had been lacking adequate signage posted.

   There is significant delay in bloom toxin assessment that could be dangerous if left unposted to await results. And, many blooms could die, and the water clear up, but the toxins only be dispersed when the dead cyanobacteria degrade on the lake bottom, with serious exposures to swimmers that swam in clear water but heard nothing of the bloom (or were given a premature 'all clear'. HABS advisories may even sometimes be lifted, yet the toxin dispersal delayed.

   Then, there are more unknowns in that there are emerging newly identified toxins (e.g. N-BMAA), that could accumulate in fish and shellfish to be eaten. 

   There is a lot of public education needed, and what do we say on signage?

    

2. Glad I don't have a shower system set up out of a lake with frequent HABs. I know quite a few who do.

3. Sailors often say that they can smell that they are approaching land, even before they can see it. When I drive toward the ocean, I can smell it before I can see it. The US pacific coast surf picks up and carries sulphur compounds inland to land as dry deposition on vegetation during dry periods, and as wet deposition in wet weather. The S can become acidification pressure needing buffering, damaging vegetation, and dripping to the soil,lowering the pH and tying up the available calcium as less available bicarbonate. Lowering pH can then mobilize toxic metals to add toxicity in the system. 

4. When testing for the HABs toxins, it may become important to include N-BMAA. Recent research about BMAA toxin becoming nitrosated to N-BMAA, resulting in a higher level of neurotoxic effect, may now cause a higher level of concern. BMAA research is emerging as a suggested neurotoxin associated with ALS increased occurrence in Guam, and by extension is being investigated as potentially additive or even possible causative in several neurologic diseases. Much of the early research has been inconclusive on the whole, but remains a troubling possibility for public health. The December 2017 research on N-BMAA may raise even higher interest in further research.