Researchers have found that areas with frequent blue-green algae blooms also have a higher death rate from liver disease. TYLER TREADWAY/TCPALM
People living in areas with significant blue-green algae blooms, including the Treasure Coast, are more likely to die from nonalcoholic liver disease than those who don’t.
Martin, St. Lucie, Indian River and Okeechobee counties make up a striking “cluster” with a high rate of both blooms and deaths, according to Ohio State University researchers. It’s the only such cluster in Florida and one of 65 scientists found nationwide.
In fact, the death rate from liver disease not related to alcohol was nearly twice as high in the four counties as the national rate during the 12 years of the OSU study, according to data calculated for TCPalm by the Centers for Disease Control and Prevention.
While the study found a suspicious link between the toxin, called microsystin, that’s commonly found in blue-green algae, called cyanobacteria, it did not go so far as to confirm that blooms cause liver disease, especially not in particular individuals.
“We didn’t find a causal relationship. We can’t say that exposure to blooms causes liver disease,” said study co-author Jiyoung Lee, an OSU professor of environmental health sciences. “That’s a hypothesis for another study to look at.”
Finding a correlation is an important first step, said Edith “Edie” Widder, founder and lead scientist at the Ocean Research & Conservation Association in Fort Pierce.
“It’s shocking that there’s only one of these clusters in Florida — and it’s us,” Widder said. “Remember how seeing that a lot of people who smoked developed cancer led to the discovery that smoking causes cancer? We don’t want to end up 20 years from now with lots of folks with liver disease on the Treasure Coast because we ignored the warning signs.”
Researchers compared data on blooms and deaths at the county and national levels from 1999 to 2010, “but we have no clue what was going on at the individual level,” said Song Liang, who worked on the study while at OSU but has been teaching at the University of Florida since 2013.
Liver disease can have numerous causes besides chronic alcohol use, including genetics, cancers, obesity, parasites and viruses, such as hepatitis viruses.
TCPalm’s analysis found there were three large Lake Okeechobee discharges that caused widespread algae blooms in the St. Lucie River and Indian River Lagoon in Martin and St. Lucie counties during the 10-year study period:
- 163.2 billion gallons from April 2003 to April 2004
- 457.2 billion gallons from September 2004 to April 2006
- 83.7 billion gallons from March to September 2010
Of those, the worst were the discharges spanning 21 months from September 2004 to April 2006 — when hurricanes Frances, Jeanne and Wilma hit the Treasure Coast.
The study, published in the May 2015 edition of Environmental Health, did not include blooms that coincided with lake discharges in 2013 and 2016, although Liang said he wants to do a follow-up study into them. Longtime observers consider the “Mean Green 2016” blooms to be the worst ever, for several reasons:
- Many of the blooms Martin County and the Florida Department of Environmental Protection sampled had toxin levels well above the 10 parts per billion the World Health Organization considers hazardous in recreational physical contact.
- Water at Central Marine on the river’s north shore in Stuart was more than 3,000 times the safe limit.
- It was the first time algae covered Atlantic beaches, from Bathtub Reef Beach at the St. Lucie Inlet as far north as the Jensen Beach public beach and as far south as the Hobe Sound public beach.
- The 237 billion gallons discharged were about two-thirds more than in 2003-04 and about a third more than in 2010.
Indian River County
Indian River County doesn’t get blankets of blue-green algae like those in the St. Lucie River, but there are “cryptic bacteria blooms” in the county’s canals where ORCA has remote-controlled water quality monitors, called Kilroys, Widder said.
“They are cryptic in the sense that they don’t show up as visible green slime at the surface, but they are plenty concentrated enough to be of concern,” Widder wrote in an email. “They may well be a source of microcystin, but we cannot say that definitively since we didn’t measure for the toxin.”
Kilroys also have found high levels of blue-green algae in the C-23 and C-24 canals, which dump runoff from farms and ranches in western Martin and St. Lucie counties into the North Fork of the St. Lucie River.
Lake Okeechobee had 109 algae blooms in the five years ending just before summer 2016, when a 33-square-mile bloom eventually spread out of the lake into the St. Lucie River, according to the South Florida Water Management District. The toxin was found in 46 of the lake’s blooms.
“It is hard to say how often blooms occur because of the size and variability of the lake,” said Paul Gray, Audubon Florida’s Lake O specialist. “But suffice it to say it is a problem.”
Ounce of prevention
Algae toxins can cause nausea and vomiting if ingested; rash or hay fever symptoms if touched or inhaled; and liver disease if drank.
“Just looking at a bloom, you can’t tell if it has toxins,” said Lee, the OSU professor.
People should limit how much fish they eat from water prone to blooms because thorough cooking won’t kill the toxins and boiling water only concentrates them, Lee said.
“The toxin can accumulate in fish, mostly in their livers, but not the flesh that people eat,” Lee said. “Still, I would be careful eating fish from the river. At most, eat fish once a week.”
Breathing it is worse than touching it, Widder said. “Along with drinking it in water and eating in food, breathing it in is the most effective way for the toxins to enter your body,” she said.
Martin County studies last year found toxins in the air around one of the river blooms, but at a rate about seven times lower than the limit for safe inhalation, according to the Florida Health Department, which erected signs warning people not to touch the water.
Lee, who currently is studying how plants absorb toxins, also recommended not using algae-rich water for irrigation. That’s also a concern of Widder’s, especially as former citrus groves on the Treasure Coast are replanted with row crops. Rice and leafy green vegetables are known to take in microcystin, Widder said. Tomatoes don’t.
“Here in Florida, we irrigate our crops with canal water, and that canal water can contain blue-green algae with microcystin,” Widder said, “and we know that a lot of food crops can take up microcystin.”
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