Multiple blooms, multiple toxins, multiple worries: New study sheds light on 2018's disastrous algae crisis in Florida
Florida algae crisis: Scientists test the Caloosahatchee’s toxic bloom The News-Press
Those who lived through 2018’s summer knew Southwest Florida’s water was bad, but a new peer-reviewed scientific study helps clarify how bad.
Just published in the journal Neurotoxicity Research, the paper shows residents were exposed to a mix of potentially dangerous toxins at the same time, as a one-two punch of algae blooms left the economy reeling and residents sickened.
In coastal saltwater, red tide killed countless sea creatures, while making beachgoing miserable for many. Throughout freshwater inland reaches, cyanobacteria glazed the Caloosahatchee, its tributaries and connected canals. The result was an ugly, stinking mess that may have lasting health consequences for the people who experienced it.
The paper’s lead author is James Metcalf, senior research scientist at Brain Chemistry Labs in Wyoming. The title: "Toxin Analysis of Freshwater Cyanobacterial and Marine Harmful Algal Blooms on the West Coast of Florida and Implications for Estuarine Environments.”
With the help of volunteers and staff from the nonprofits Calusa Waterkeeper and Sanibel-Captiva Conservation Foundation, Metcalf collected samples with a pennon-shaped white mesh net device that snags and concentrates algae. He crisscrossed the region’s waterways by boat, ranging from Fort Myers to Pine Island Sound to Gasparilla Island, dipping up specimens from open water, marinas and matted scum along seawalls.
“Although aesthetically unpleasant,” Metcalf writes in the study, “of bigger concern is their potential to produce highly potent, low molecular weight toxins with acute and chronic human health impacts.” Beyond skin irritation and gastrointestinal distress, the toxins have been implicated in liver disease and several grave neurodegenerative illnesses.
Just as the crisis had multiple causes, the resulting blooms released multiple toxins linked to human illness.
According to the report, water samples showed high concentrations of microcystin-LR, produced by cyanobacteria, often called blue-green algae, “sufficient to result in adverse human and animal health effects if ingested.”
At the same time the microorganism that produced red tide were releasing a potent neurotoxin called brevetoxin in the Gulf of Mexico.
What’s more, another neurotoxin called BMAA linked to neurodegenerative diseases such as ALS and Alzheimer's disease, was detected in samples from the Caloosahatchee and west coast. (Sampling the following year showed high concentrations of BMAA to be present then as well.)
Together, they created what Cassani calls a 'nightmare of co-occurring toxins.'
Another concern is the tendency of these compounds to bio-accumulate – that is, become more concentrated in the tissues of top-of-food chain animals, Cassani explains. Teeny marine critters get eaten by small fish; who are eaten by medium fish, who are eaten by large fish who are then eaten by top predators like sharks, dolphins or humans.
“These are stable molecules that don’t deteriorate rapidly, and they stay in the issues of the organisms that ingest them, who then inherit the load of that toxin,” he said. “So the next question is, ‘How much risk am I at?’ And that’s not an easy question, because risk depends on a lot of variables: Are you old? Or young? Or exposed to an acute dose every day as opposed to once on vacation. So it’s hard to generalize.”
FGCU professor Barry Rosen, who specializes in algae, has a few reservations about the paper, but overall, characterizes the research as “clean.” Rosen thinks too much blame is placed on Lake Okeechobee for the presence of cyanobacteria. While lake discharges are a source of the toxin-producing algae, he also points out that the Caloosahatchee and surrounding watershed can produce blooms independent of the lake.
However, he doesn’t disagree with its connecting BMAA to brain disease. “I do believe if BMAA is truly present, that it could be involved in neurotoxicity.
Metcalf emphasizes that the idea wasn't to cause panic.
"The nature of research is that we’re constantly asking questions, doing experiments, collecting data and trying to understand what’s going on." he said. "We’re trying to provide basic information so that people like legislators and the public can make informed decisions about what is the potential risk.”
Studies like this add to the growing body of evidence that such blooms can endanger people, and government agencies need to take the research seriously, Cassani said.
Frustrated at what they see as a hands-off attitude toward water-related health risks, Waterkeepers around the state have urged state agencies to warn citizens about the potential dangers of harmful algae blooms. This study adds more urgency to their concerns.
"It's another scary outcome from peer-reviewed science," Cassani said. "How long do we have to wait for some decision threshold about risk? How many people have to be impacted?"
Officials often are reluctant to take action on science that’s not yet settled, he said
“You’ll hear a lot of government agencies saying if the cause and effect is not absolutely known, we’re going to take a very conservative approach to it,” Cassani said. “But at what point do we have a good enough handle on the variables to say for sure when there’s enough certainty about risk?
“A lot of us are getting very frustrated because there’s never enough science if there’s no political will.”
Early in Gov. Ron DeSantis’ administration, Cassani recalls, “(DeSantis) said, ‘Swing for the fences and err on the side of caution,’ but in this age of discounting science, I just don’t see that we’re erring on the side of caution … And of course, if you’re a local or state government, you don’t want to deal with that potential liability.”
Sanibel water advocate Howard Simon is more pointed: “This study tells us what Florida environmental protection and health officials should have warned us about in 2018: Exposure to the toxin-laden waters that were released from Lake Okeechobee and sent down the Caloosahatchee River and St. Lucie Canal were a risk factor for liver cancer and neurodegenerative diseases like ALS and Alzheimer’s,” Simon wrote in an email.
“Sadly," he wrote, "until the pollution of our waters, largely from agri-business and developers, is effectively addressed – and by more than the half-measures trumpeted by the Legislature in this last session – people need to think of exposure to our waters and the risk of neurodegenerative diseases somewhat like smoking: Just because you smoke doesn’t mean you will get lung cancer, but it certainly will increase your risk.”
Metcalf also uses the smoking/cancer analogy. For years, he says, many people didn’t believe smoking could cause cancer.
Further complicating the connection was the fact that “some people can smoke for 20 years and not get cancer, but some people cannot smoke a cigarette in their lives and get lung cancer at 46,” Metcalf said. “So genes can play a role … and there’s probably other things in the environment that can cause ALS but I do think that the research suggests that exposure cyanobacteria is a risk factor for neurologic disease.”
He allows that there are publications and data that conflict with his team’s findings, “But to just say there’s no link? I think, in fact, it’s quite the opposite,” Metcalf said.
Several locally familiar environmental advocates share authorship credits with Metcalf's peer-reviewed paper: Sanibel-Captiva Conservation’s recently retired natural resource policy director Rae Ann Wessel and Calusa Waterkeeper’s Cassani and Jason Pim.
"It was a true collaboration," Metcalf said. "We couldn't have done it without their help."