Blooms of toxic algae have been reported in eight of the 11 Finger Lakes this year — the most since the state began tracking their spread in 2012. The trend poses a distinct threat to swimmers, pets and public drinking water.
Beaches on Cayuga, Keuka and Honeoye lakes were closed for several days in late July and early August after multiple harmful algal blooms, or HABs, were reported.
Hemlock and Canadice lakes, which have been supplying high-quality drinking water to Rochester for more than a century, had their first reports of algal blooms this summer. They dissipated quickly and weren’t thought to be an immediate threat Rochester’s water supply.
But last October, detectable algal toxins turned up in treated drinking water in the towns of Auburn and Owasco, which draw water from Owasco Lake. Of all the Finger Lakes, Honeoye and Owasco have been hit the hardest by HABs. Tests this month showed detectable algal toxins in Auburn’s raw water, though not in its treated water.
HABs, which typically appear as green scum on the water’s surface, produce cyanobacteria that release potent liver and nerve toxins. They thrive in warm, nutrient-rich, calm water. They don’t survive for long after wind and waves pick up or waters cool. Worldwide, cyanobacteria blooms have been associated with mass fish kills, wildlife deaths and irreversible neurological disease in humans, Scientific American has reported.
Blooms have been documented for more than a century. But their frequency has increased drastically in the past few years, affecting water bodies in Switzerland, Uganda, Guam, China and Russia, the magazine said.
Western Lake Erie has been particularly vulnerable to algal blooms containing microcystin, a common type of cyanotoxin. In 2014, the city of Toledo, Ohio, issued a drinking water warning after a treatment plant that supplies 500,000 people reported a microcystin level of 3.191 parts per billion, well above the World Health Organization’s limit of 1 ppb.
(Auburn’s raw water registered 0.16 ppb this year. Last year, Auburn’s treated water also registered 0.16ppb, while Owasco’s was 0.18ppb. The U.S. Environmental Protection Agency’s health advisory level for pre-school children is 0.30ppb.)
Scientists are now probing potential links between HABs and neurological diseases in humans such as dementia, Alzheimer’s, Parkinson’s and Amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease.
While no research has confirmed any such link, doctors and researchers at Dartmourth-Hitchcock Medical Center have noticed ALS hot spots in New England, including Lake Mascoma in New Hampshire. The lake is prone to algal blooms, and the incidence of ALS among people living near the lake was reported to be 25 times higher than expected. Also, traces of cyanotoxins have been found in the lungs of those who died of ALS. Another peer-reviewed scientific research report linked cyanobacteria with the deaths of more than 200 dogs between 1920 and 2012.
Blue-green algae is present in small, benign amounts in virtually all water bodies. In later summer when the water temperatures are highest, they tend to explode into blooms. HABs are nearly impossible to distinguish from other types of algae scum that are common and harmless.
The New York State Department of Environmental Conservation tracks reports of blooms on its website, and it warns people to keep their distance from any suspicious scum: “People, pets and livestock should avoid contact with water that is discolored or has algae scum on the surface. Colors can include shades of green, blue-green, yellow, brown or red.”
Lab tests can confirm whether an algal bloom is toxic, but many reports go untested.
After several reports of algal blooms along the southern shoreline of Cayuga Lake in late July, the DEC said it had confirmed the presence of HABs. In response, the Ithaca Yacht Club and Taughannock Falls State Park closed their beaches for several days.
For Seneca Lake, the first reports of HABs came in 2015, and high toxins were confirmed there in 2016. Dozens of volunteers organized by Seneca Lake Pure Waters Association were assigned to monitor sections of lake shore this summer. But so far, there haven’t been reported blooms on Seneca in 2017, according to the DEC website. Unseasonably cool weather in late August and early September may have contributed to the respite.
Previous Seneca Lake blooms were located near streams that are high in nutrients from farm runoff, water treatment plants or other sources. The nutrients were seen as a contributing cause.
For example, blooms reported at Kime Beach on the lake’s northeast end may be attributed in part to runoff from Reeder Creek, three miles south. Reeder has shown exceptionally high levels of phosphorous, which may be traceable to the disposal of munitions at the Seneca Army Depot.
Another Seneca Lake bloom with lab-confirmed high toxins occurred at Perry Point, just south of the Keuka Outlet, which also tends to be high in nutrients.
In addition, higher lake water temperatures around Dresden due to massive warm water discharges from the Greenidge power plant may be another risk factor.
Gregory Boyer, a geochemist who heads the Syracuse laboratory that confirmed Seneca Lake’s HABs, stated in a January affidavit that Greenidge-warmed water around Dresden boosts chances for toxic blooms in the area.
Boyer filed his affidavit on behalf of the Sierra Club in its bid to force the DEC to require an environmental impact statement for power plant. In it he wrote:
“I am of the opinion that increasing water temperatures in the Dresden bay area of Seneca lake could result in increased HABs outbreaks in that area and that this issue deserves further study before proceeding forward.”
The DEC had decided months earlier that Greenidge didn’t need to prepare an environmental impact statement. At a court hearing in January, lawyers for the agency asked a state Supreme Court judge to disregard Boyer’s affidavit.
Weeks later, Greenidge started plant operations without an environmental impact statement. Days later, the judge dismissed the Sierra Club suit.
The Sierra Club has appealed.