When Lake Champlain is freezing over, its stinking pea-green algae blooms seem like a distant memory. But the potential health threat of cyanobacteria, which produce many toxins, is an all-season concern for scientists.
In particular, a Dartmouth-Hitchcock Medical Center neurologist noticed that a cluster of his ALS patients lived near Mascoma Lake in New Hampshire, where cyanobacteria bloom. Amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease, is a degenerative brain condition that results in progressive muscle weakness, paralysis and, eventually, respiratory failure.
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Elijah Stommel has also identified ALS clusters near Lake Champlain and other lakes in New Hampshire.
Because some of the ALS patients in the clusters never swam, ate fish or got their drinking water from the lakes, Stommel looked to airborne sources. He partnered with James Haney, a professor at the University of New Hampshire Center for Freshwater Biology, to research the toxicity of aerosols from algae blooms. Researchers collected the aerosols — airborne mists of tiny particles or cells — at lakes in New Hampshire and Vermont.
Of interest to the New Hampshire researchers is a particular neurotoxin commonly known as BMAA. Research has suggested a link to human brain disease, though some experts and health officials are skeptical.
BMAA has been implicated in a paralytic condition that afflicted a native population in Guam. This condition was marked by tangles and clumps in the brain tissue of victims that look similar to the ravages of Parkinson’s, ALS and dementia. Cyanobacteria, which aren’t confined to watery environments, grow on the roots of the cycad tree in Guam and produce BMAA, which gets into the tree seeds. Fruit bats eat the seeds, and the native population eats the fruit bats. Scientists made that particular BMAA link in 2002.
Meanwhile, a study published last month in Proceedings of the Royal Society showed that monkeys fed both high and low doses of BMAA developed the tangled neural fibers and protein clumps typical of Alzheimer’s.
Back in New England, Stommel and Haney are exploring whether airborne algae particles expose people to BMAA. In one study of fish and aerosols from Mascoma Lake in Enfield, N.H., where the number of ALS cases was 25 times higher than expected, they found BMAA in both the carp and the air samples.
The study doesn’t show that BMAA causes ALS, their report, published a year ago, concluded. But the researchers did say it strengthened the association Stommel first identified when he mapped his patients, and they are continuing to study aerosol samples from New Hampshire and Vermont.
“What we are stating is a hypothesis,” Haney said. “It is a question. It is not that we have the answer.”
“No one wants to create a panic,” Haney continued, but he noted, “There is certainly a lot more information now than there was a year ago. It is not just a wild idea.”
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Sarah Vose, toxicologist with the Vermont Department of Health, is not convinced. “The published research on ALS cases near lakes and ponds with cyanobacteria blooms is epidemiologically weak,” she wrote in an email response to Seven Days. “The methods used by the authors do not account for other factors that can contribute to ALS, including age and exposure to pesticides and metals.”
Although the health department acknowledges Stommel’s ALS cluster research on its website, Vose said, “We have concerns about strong conclusions being drawn without more rigorous studies. This line of research is very preliminary.”
Vose said there is no question that blue-green algae in Vermont lakes sometimes produce toxins, including microcystins, which are harmful to the liver. Some people develop rashes upon contact, Vose said. If people swallow water containing cyanobacteria cells or toxins, they might get stomach cramps, feel nauseated or vomit. The deaths of two dogs, in 1999 and 2000, were attributed to their exposure to water from toxic blooms in Lake Champlain.
Because of the potential health hazards, the state maintains a map of blooms on the Department of Health website throughout the summer.
“Many of the managed recreation areas in the state follow the health department’s advice to close beaches when cyanobacteria are present,” Vose said. “And they test the water when the bloom is gone to see if the bloom left any toxins behind.”
Last summer the Department of Health also tested all 22 drinking water systems that draw from Lake Champlain. No toxins showed up, Vose said.
Mike Winslow, staff scientist with the Lake Champlain Committee, shares the health department’s skepticism about a link between algae blooms and ALS. “I don’t have a lot of faith in the cluster work at all,” said the biologist, who has worked for the LCC since 2001. Formed in 1963, it offers education and advocacy for the lake’s health and accessibility.
Winslow trains the volunteer lake monitors who submit weekly bloom reports to the state during the summer. “Part of the training is talking about risks,” he said.
Winslow also helps identify research projects for the Lake Champlain Basin Program, as chair of its technical advisory committee. The program helps fund initiatives that protect and restore the lake and its watershed.
Currently the program is seeking researchers for a new study that would examine several species of fish for the presence of mercury and toxins produced in algae blooms. The algal toxin portion of the study will try to determine if it is safe to handle and eat fish caught near blooms. Winslow said there’s no plan to look for BMAA in the fish because the neurotoxin is too difficult to measure.
Winslow argues that cyanobacteria are everywhere — in fresh and salt water, and in soil. They form symbiotic relationships with fungi to make lichens. “As a result, everyone is exposed to blue-green algae at some level, but only a small subset develops neurodegenerative diseases,” he said. He worries that publicity about a speculative link between blooms and ALS will panic people: “I don’t want to scare people away from the lake."
James Ehlers, executive director of Lake Champlain International, a nonprofit that sponsors a fishing derby and promotes lake health, said he hopes research eventually dispels a link between cyanobacteria blooms and diseases such as ALS. But he disagrees with Winslow and Vose about downplaying the research because it is preliminary.
“These are world-renowned researchers and physicians, and their scientific inquiry deserves public support,” Ehlers said. “Sticking our heads in the sand isn’t the way to rule this out."
“We are certainly not saying this is definitive,” Ehlers continued. “But there is enough here that it merits asking questions. People have a right to know. If I lived on St. Albans Bay, I’d want to know this research is being conducted.”
Christopher Kilian, vice president and director of the Conservation Law Foundation in Vermont, is also keeping tabs on the research. He argues that even the possibility that cyanobacteria blooms could create a risk for neurological diseases should increase the urgency to clean up the lake.
Last year, the State of Vermont reached an agreement with the U.S. Environmental Protection Agency to reduce the algae-fueling phosphorous runoff into Lake Champlain. A CLF lawsuit in 2008 had challenged the adequacy of the state’s earlier cleanup plan and led to the new agreement, as well as legislation enacted last spring to provide funding and staff to begin the work.
Like Ehlers, Kilian thinks the public isn’t getting enough information about this possible health risk. He cited an analysis of the research on the many potential health effects associated with toxic cyanobacteria published a year ago in Current Environmental Health Reports that concluded, “We propose a guilty-until- proven-innocent approach to cyanobacterial harmful algal bloom management … to safeguard public health from both known and unknown cyanobacterial risks.”
In a radio interview, Kilian said he personally would avoid swimming, boating or having any kind of exposure to cyanobacteria blooms. He told Seven Days he’s concerned that the current monitoring program requires volunteers to get near blooms to take samples.
Kilian would like to see monitoring specifically for the BMAA toxin, support for deployment of aerosol monitoring equipment and research on how far aerosols travel. “And the time frames for cleanup need to be much shorter,” he said. “We should be acting aggressively to protect people.”
Stommel is on the same page. “If one could identify a risk factor, you might be able to mitigate,” said the neurologist. “I’m not trying to ring any alarm bells. I’m trying to do science.”
In the meantime, Stommel said, “I think you want to avoid exposure to active blooms. But if you live on a lake, you don’t need to pack up your bags."