Green algae fouls Lake Washington

Florida Today

Green algae covered water near the banks of Lake Washington Friday (July 19, 2019). The lake is a main drinking water supply for Melbourne's water utility.

MELBOURNE — Mark Maida cast his bait beyond pea-green streaks of slime near the banks of Lake Washington, where a potentially toxin-producing algae lingers in the main source of drinking water for more than 170,000 people.

The city hasn't found any algae toxins yet and assures the drinking water's safe. Any algae toxins from Lake Washington would be removed from the water before it reaches customers' taps, city officials say.

But green wasn't a good look for the lake this week.

"It's nasty," Maida said Friday from Lake Washington's fishing pier. "Normally, you can see the bottom. The fish can't see the bait." Maida won't eat his catches. He tosses back what he hooks — mostly small gar.

Bright-green algae blanketed waters near the lake's banks this week. The algae altered how the city disinfects its water, resulting in about 60 customer complaints of a strange odor to their drinking water. Excess algae has become an every-summer scourge for many Florida lakes, including Lake Washington. Rains bring remnants of fertilizers, leaky septic and sewer systems, and land-applied sewage sludge to fuel the algae explosions, sometimes toxic. Hot temperatures further fuel the algae growth.

"The algae is causing us to change our water production procedures," said Cheryl Mall, city spokeswoman. "Our water is being treated and it's safe."

This microscope image shows Dolichospermum circinale, one of the 28 species of cyanobacteria USGS scientists discovered during a major harmful algal bloom that hit southern Florida in 1999. Many varieties of cyanobacteria can emit toxins. This species is capable of creating saxitoxin, which is the second most potent natural toxin in the world.

Lake Washington provides two-thirds of the water supply for the city's 57,000 connections serving about 170,000 people. The rest comes from wells.

Beyond its city limits, Melbourne also supplies drinking water to Melbourne Beach, Indialantic, Indian Harbour Beach, Satellite Beach, Palm Shores, Melbourne Village and part of the unincorporated areas south of the Pineda Causeway. Melbourne also provides wholesale water service to West Melbourne.

Mark Maida, of Melbourne, fishes from a pier at Lake Washington Friday (July 19, 2019), as algae coats the waters close to shore. The lake is a main source of drinking water for more than 170,000 people.

City testing of Lake Washington on July 10 found a potentially toxic algae, or cyanobacteria, called Dolichospermum circinale. That means there is a cyanobacteria "that could produce a toxin such as microcystins," Shaniese Alexander, laboratory supervisory in the city’s Public Works department, said via email. "To date, we have not found any cyanobacteria where microcystins has been detected in our source waters."

According to the U.S. Geological Survey, that algae species also is capable of creating saxitoxin, the second most potent natural toxin in the world.

Puffer fish in the Indian River Lagoon have been off-limits to harvest since 2002, after some people almost died after eating the fish contaminated with saxitoxin — a poison 1,000 times more lethal than cyanide. At least 28 people got sick in 2002 and 2003 after they ate puffer fish caught in the Titusville area, leading to a permanent state ban on harvesting the fish.

"Any potentially toxigenic cyanobacteria is removed during our treatment process," Mall said.

An air boat cruises near the boat ramp at Lake Washington Friday, where green algae blankets the lake.

Large patches and streaks of green algae drifted near the lake's shores Thursday and Friday.

"It was like kayaking in pea soup," Bill Zoby said of taking water samples from the lake Thursday. He's on the nonprofit St Johns Riverkeeper Headwaters Advisory Council. "The gas from the algae was bubbling up and giving off awful smells."

"I am still coughing, itchy eyes and a sore throat from the gases," Zoby said Thursday.

Blue-green algae is blooming in Lake Washington, according to St. Johns Riverkeeper, a nonprofit group that monitors lake health. One of the groups members recently pulled this glass of water from the lake.

Winter and spring rains and record summer heat help to set the stage for algae blooms in the lake this month. Rains pulse in nitrogen and phosphorus from land. Those two nutrients come from farm and residential fertilizers, leaky sewage systems and the sewage sludge that municipalities spread on land.

The recent city testing ruled out a toxic blue-green algae, called microcystis, that is linked with short and long-term health risks, such as liver disease. The toxin the algae emits, microcystin, shut down Toledo's water supply or a few days in 2014 and has for years occasionally nagged at Melbourne and other Florida utilities that tap lake or river water. The algae commonly blooms in Central and South Florida, and is toxic to fish, plants, invertebrates and mammals, including humans.

The toxin can magnify in mussels, crayfish, fish and crops irrigated with contaminated water.

Microcystin ingestion can cause diarrhea and abdominal cramps. Swimming in water where the toxin is present can cause rashes. Microcystin has been linked with liver cancer in lab mice, but its long-term effects on humans are less certain.

More tests samples of Lake Washington are planned for next week, officials said.

Jim Waymer is environment reporter at FLORIDA TODAY.

Contact Waymer at 321-242-3663

or jwaymer@floridatoday.com.

Twitter: @JWayEnviro

Facebook: www.facebook.com/jim.waymer

Support local journalism: It you would like to read more government and political news, and you are not a subscriber, please consider subscribing. For details, go to offers.floridatoday.com.