Cayuga Lake Reports First Algal Toxins; Blooms Recede, but Dangers Linger

High toxins from cyanobacteria, or blue-green algae, were recently confirmed for the first time in Cayuga Lake, the sixth of the 11 Finger Lakes to be afflicted by the widespread health crisis this summer.
Meanwhile, three new toxin hot spots were reported on Seneca Lake, and the cities of Syracuse and Auburn said trace levels of algal toxins had returned to their raw water from Skaneateles and Owasco lakes, respectively.
The Cayuga high toxin report came from a sample taken near Bonnie Banks Road in the lake’s northwest quadrant, about three miles south of the town of Seneca Falls.
The new Seneca Lake sites found to have high toxins were located at the Seneca Lake State Park in Geneva, Combs Road in Ovid and Spirawk Road in Hector, according to an updated Seneca Lake Pure Waters Association interactive map. Five earlier high toxin readings from Seneca came from sites in the lake’s northwest quadrant.
Although the visible cyanobacterias blooms have abated in recent days, toxins they create may linger.
When can lakefront owners be confident it’s OK to drink and use lake water? Asked that question Saturday at a forum in Ithaca on harmful algal blooms, or HABs, state health and environment officials declined to give a specific date.
“There is uncertainty around that,” said Adriel Shea of the Tompkins County Health Department. “There’s definitely a gap in our knowledge of how long these toxins will last. It seems that they will dissipate quite quickly. But will they drop to the level that is safe for consumption? It’s just really hard to know at the moment.”
Shea, speaking at the Community Science Institute forum, noted that lake water intake pipes and even beach wells are highly susceptible to contaminates in lake water. He said the state Department of Health does not endorse any home treatment system, including boiling the water. He urged people to use bottled water until further notice.
The most common type of cyanobacteria found in the Finger Lakes this year produces microcystin, a nerve and liver toxin. Exposure to such blue-green algal toxins have been associated in scientific studies with irreversible neurological diseases, including dementia, Alzheimer’s, Parkinson’s and ALS (Lou Gehrig’s disease).
Contact with the toxins from swimming or breathing can cause irritation of the skin, eyes, nose and throat. Dogs in particular are at risk because they are attracted to the toxins’ smell and can be poisoned by grooming after a swim.
The dangers of cyanobacteria were highlighted in 2014 when dangerous levels of microcystin turned up the public drinking water in Toledo, Ohio. That August, 500,000 people were told not to drink their tap water — a ban that lasted for several days.
Lake Erie — Toledo’s source of raw water — has been plagued by algal blooms ever since. But the use of powdered activated charcoal filtering has kept measurable toxins out of Toledo’s public drinking water since August 2014.
Earlier this month, raw lake water taken by the cites Syracuse and Auburn had shown trace amounts of microcystin before appearing to clear up. Then last week those trace levels returned in their raw water, although filtering and treatment kept any from reaching public drinking water, health officials said. (Last summer, trace levels of toxins did in fact reach Auburn’s drinking water.)
Owasco Lake raw water samples collected Sept. 27 at Auburn’s water treatment plant measured 0.25 micrograms of microcystin per liter, according to the Cayuga County Health Dept. The U.S. Environmental Protection Agency advisory level for microcystin is 0.3 micrograms per liter.
Previously, microcystin levels in Auburn’s raw water had been 0.18 micrograms per liter on Aug. 31 and 0.16 on Sept. 18, auburnpub.com reported.
At Skaneateles Lake, toxins were again detected in Syracuse’s raw water on Oct. 1 after a nine-day break. Readings at the Syracuse water system’s gatehouse there were 0.16 micrograms per liter, syracuse.com reported. Syracuse has been mixing its water from Skaneateles with water from Lake Ontario and treating it with chlorine.
An unseasonably warm September in the wake of heavy rain events earlier in the summer has fueled by far the worst Finger Lakes outbreak of harmful algal blooms, or HABs, in recent memory.
When the state Department of Environmental Conservation began tracking HABs closely in 2012, Owasco and Honeoye were the only Finger Lakes affected. By 2014, four Finger Lakes reported HABs, and in 2015 and 2016, six of the 11 had been hit.
But this summer all 11 of the Finger Lakes reported HABs, six of those with confirmed high toxins that affect the liver and the nervous system.
Cyanobacteria tend to thrive in the late summer, particularly when they have nutrients (nitrogen and phosphorus), warm water, ample sunlight and calm water.
Hardy enough to have survived for some three billion years, they have adapted to “out-compete many other forms of plankton for nitrogen,” according to Lisa Cleckner, director of the Finger Lakes Institute in Geneva.
Cleckner advised again panic because cyanobacteria blooms “have been happening for years.” Better reporting — New York has one of the nation’s most active monitoring systems — has made 2017 seem especially bad, she said.
Unseasonably warm weather contributed to September’s rash of blooms, but it doesn’t explain why Hemlock and Canadice lakes were affected for the first time in July.
Those lakes have some of the lowest nutrient levels in the Finger Lakes and they had never been known to have suffered from HABs, said Tony Prestigiacomo, of the state Department of Environmental Conservation. Those blooms (which have not been reported as toxic) followed heavy rainstorms.
The DEC’s Finger Lakes Water Hub program has helped develop and coordinate volunteer lake monitoring programs for several of the larger lakes, beginning with Owasco and Seneca, and lately Cayuga.
Although the DEC is working to understand the role nutrients play in algal blooms, Prestigiacomo said, the agency has not yet factored HABs into its program to develop updated total maximum daily loads, or TMDLs, allowed for nitrogen, phosphorus, pathogens and other substances.