Is Lake O toxic algae harmful by air? CDC study aims to find out

Bobbing bright green on idle waters, a microsystis bloom is conspicuous and mostly avoidable.

But disturbed, churned up by boat propellers or jet ski engines, the single-celled organism, a type of cyanobacteria known as blue-green algae, can hang suspended in the air – aerosolized into a toxin-tainted fog and inhaled.

The Centers for Disease Control and Prevention are targeting Florida for a study on people who unwittingly breathe in the algae vapor, specifically those who live and work near Lake Okeechobee and the northern estuaries.

Noted in the Federal Register last month, the study would choose 50 people “highly exposed” to the harmful algae blooms for testing of cyanobacteria levels in their systems.

CDC officials said Lake Okeechobee’s algae plague was brought to their attention by Republican U.S. Reps. Brian Mast, of Palm City, and Francis Rooney, of Naples.

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“We know that if you ingest it, it can get in your bloodstream and cause liver damage and all sorts of other problems,” said Malcolm McFarland, a research associate at Florida Atlantic University’s Harbor Branch Oceanographic Institute in Fort Pierce. “But we haven’t really known how exposed people are when they are regularly boating and fishing and how being aerosolized is a potential route of exposure to people.”

McFarland said the proposed CDC study is especially important because blue-green algae-slathered waterways are a nationwide problem that’s not going away anytime soon.

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Enhanced rainfall triggered by a warmer climate will funnel more nutrients into water bodies, such as Lake Okeechobee, where the cyanobacteria thrive during the longer, hotter days of summer.

This past summer, algae outbreaks caused swimming bans from Oregon to Mississippi’s gulf coast beaches, which suffered large flushes of freshwater into the Gulf of Mexico from heavy Midwest rains. Harmful algae blooms in Lake Erie have been so persistent, the National Weather Service issues bloom forecasts July through early fall for the fourth largest of the Great Lakes.

“We’re not alone in Florida in struggling with this,” said Florida Surgeon General Scott Rivekees during a Blue Green Algae Task Force meeting last month. “More than half the states in the U.S. are dealing with this.”

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Despite the extensive and deepening problem, Florida toxicologist Kendra Goff said research about how algae blooms affect people’s health are sparse. How people are exposed, the duration of exposure and the frequency of exposure are all areas that still need study.

Most documented illnesses from algae contact are self-reported – leaving evidence gaps in understanding how contact occurred.

For example, hydrogen sulfide emitted by a decaying algae bloom can cause temporary respiratory problems, but people self-reporting may link it directly to inhaling blue-green algae. There is also no FDA approved clinical laboratory tests for exposure and health care professionals lack expertise in algae-related illnesses, Goff said.

“If it’s hard for us to determine what’s going on, then it’s also difficult for our health care professionals to understand what is an exposure and how that may relate to illnesses they see in their offices,” Goff said.

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Businesses, tourism was affected by outbreaks in 2016 and 2018

The blue-green algae bloom on Lake Okeechobee this past summer was much less intense than in 2018, said Richard Stumpf, an oceanographer with the National Oceanic and Atmospheric Administration who monitors algae blooms.

During the summers of 2016 and 2018, Lake Okeechobee and the St. Lucie and Caloosahatchee estuaries were choked with blue-green algae blooms so dense and stinky, it temporarily shut down businesses, disrupted tourism, and sickened dogs that drank that water.

The estuaries can get algae when lake water is released because of heavy rains. The algae on the lake goes into the estuaries, while the fresh lake water also dilutes salinity levels in the brackish rivers that would otherwise discourage algae growth.

This year, the Army Corps of Engineers went took special measures to keep Lake Okeechobee levels low ahead of the rainy season so it wasn’t forced to release water.

The CDC proposal says two similar algae studies were completed on lakes in 2006 and 2007, but toxin levels were very low on one lake, and the second study was conducted on recreational visitors who didn’t have long-term exposure.

Concern for the people fishing in canals

Diana Umpierre, an organizing representative with the Sierra Club, said she is hopeful the new proposal will target people working on the lake and estuaries but also those who regularly fish in their waters. She would also like to see recruitment for the study be conducted in multiple languages.

“Many of the people in those communities don’t have boats, but we certainly see them often along the canals fishing and we know they are eating the fish,” she said. “We also hope this study doesn't take so long that results would be slow to come and influence decisions that could further reduce risks of short and long term exposure.”

The study will run for a bloom season, approximately March through October. Results will be published in a peer-reviewed journal, but there is no timeline for completion, the CDC said. A budget is still being developed.

Comments about the study are being accepted until Nov. 18 by filling out an online form at going to regulations.gov or mailing information to Jeffrey M. Zirger, Information Collection Review Office, Centers for Disease Control and Prevention, 1600 Clifton Road, NE, MS-D74, Atlanta, GA 30329. The study should be identified as Docket No. CDC-2019-0079.

Kmiller@pbpost.com

@kmillerweather