Editor’s note: This article is by Adam Federman, a freelance writer for VTDigger.
A new study published by a team of Canadian scientists warns that exposure to blue-green algae — even in treated drinking water — can lead to gastrointestinal illness and other symptoms.
Blue-green algae, which occurs in freshwater and marine ecosystems worldwide, is commonly found in Lake Champlain and, increasingly, other bodies of water in Vermont. Scientists say toxins formed by cyanobacteria, which exist in blue-green algae, can sicken some people who come in contact with it.
One of the three research sites featured in the study was Lake Champlain’s Missisquoi Bay. A shallow, nutrient-rich bay at the lake’s northern edge it has experienced chronic and extensive algae blooms for years. According to the Canadian study the Missisquoi Bay site had the greatest number of readings that exceeded the World Health Organization’s limit for recreational water use.
The research, entitled “Prospective study of acute health effects in relation to exposure to cyanobacteria,” drew on data from 2009 and also suggests that residents might be affected by their drinking water supply.
“While it is premature to speak of a causal association,” the authors write, “it is plausible that exposure to cyanobacteria contributed to the presence of these symptoms and that the water treatment process reduced the importance of symptoms without preventing them entirely.”
They conclude that more needs to be done to inform the public of risks associated with exposure to cyanobacteria. They also note that wastewater treatment plants that process contaminated water, especially during heavy blooms, should update their management plans.
Sarah Vose, state toxicologist with the Department of Health, says the study confirms what has long been known: that contact with the toxins produced by cyanobacteria, particularly microcystins, can cause gastrointestinal illness, skin irritation, ulcers and other complications. Vose is less convinced by the author’s assessment of drinking water risks, especially as they apply to Vermont.
According to Vose, Vermont has a system in place for tracking blooms, notifying the public, and preventing exposure. If one of the lake’s many volunteer monitors (there were more than 50 this past summer) observes an algae bloom, that information is passed on to the Department of Health or DEC. If considered potentially toxic, the state agencies notify the water supplier and provide them with a test kit.
The treatment plant then tests samples of raw and treated water. If microcystin levels are more than .5 micrograms — half the WHO limit — the water supplier would be advised to test raw and treated water.
The state health advisory is 1.0 micrograms. If this level is reached a “do not drink” order may be issued. This decision is made on a case-by-case basis.
“I don’t think that people in Vermont are going to be drinking water with microcystins at or above a level that would cause concern,” says Vose.
This past summer there was just one instance in which a water supplier — the Alburgh Fire District #1 — was alerted to potentially high levels of toxic cyanobacteria. Both raw and finished water were tested and were found to be below detection levels. No further action was taken.
The part of Missisquoi Bay featured in the study is also one of the most severely affected by blue-green algae blooms. Prevailing winds tend to move algae toward the Quebec portion of the watershed, says Angela Shambaugh, aquatic biologist for the Watershed Management Division at the Agency of Natural Resources who also oversees the State’s cyanobacteria monitoring program.
Yet, according to Shambaugh, all treatment plants on the lake should be prepared for such events. The factors that set off a large bloom — air temperature, wind patterns, and nutrient levels in the lake among others — can be unpredictable. There is often a narrow window of time in which to respond. Water suppliers must be ready to act quickly, at the same time ensuring that the steps they take reduce the impacts of toxic exposure, rather than worsen them. According to an EPA reference guide published in 2012, “Applying the wrong treatment process at a specific state in treatment could damage cells and result in the release rather than removal of cyanotoxins.”
Currently there are no federal or state guidelines for cyanobacteria or their toxins in drinking water or recreational waters in the U.S. The EPA’s document seems to acknowledge that the issue needs to be addressed in a more systematic way. “It’s an area of discussion not just on Lake Champ but nationwide,” says Mike Winslow, staff scientist for the Lake Champlain Committee. The Lake Champlain Committee works annually with water suppliers, helping them to detect blooms and develop response protocols.
“This is going to be a challenge for drinking water facilities,” says Shambaugh, who has been involved in assessing blue-green algae blooms on the lake for 15 years. “Drinking water plants are really working to prepare and be ready for this.”
The most critically affected areas of the lake are Missisquoi Bay and St. Albans Bay. St. Albans does not get its water from Lake Champlain; North Hero has an intake near the outlet of Missisquoi Bay, which is monitored closely. It supplies water to about 700 dwellings.
The cyanobacteria monitoring program on Lake Champlain is now in its 13th year. It was initiated in the summer of 2000 following the deaths of two dogs from consumption of blue-green algae. Originally run by the University of Vermont in conjunction with the Lake Champlain Committee (LCC), a portion of the program was turned over to the Department of Environmental Conservation last year. LCC continues to train volunteers to collect data and reports on the results.
Links to more serious diseases
In the past decade public awareness about the potential health impacts of exposure to toxins in cyanobacteria has grown; at the same time several recent studies have explored the links between the various toxins produced by cyanobacteria and more serious illnesses such as cancer and Lou Gehrig’s disease.
“I don’t think you can overstate the problem,” says state Rep. David Deen, chair of the Fish, Wildlife, and Water Resources committee. “We know it’s happening. We know animals and people get sick.”
But how sick and with what symptoms is still largely unknown.
Researchers at Dartmouth-Hitchcock Medical Center have looked at the relationship between a particular toxin produced by cyanobacteria — beta-methylamino-L-alamine — and neurodegenerative diseases. However the authors stress that results are preliminary and it is far too early to draw conclusions. Still, even the possibility of more severe health impacts has some worried that the state is not doing enough.
Anthony Iarrapino, senior attorney with the Conservation Law Foundation, says the state needs to devote more resources to studying the long-term health impacts of cyanobacteria exposure.
“We just haven’t heard much urgency from the public health officials and from the environmental protection officials on this facet of the blue-green algae problem,” he says.
Iarrapino would like to see the state conduct a review of literature on the subject with an eye toward possibly replicating an epidemiological study here in Vermont. He also says an oversight hearing is long overdue. The EPA’s revised Total Maximum Daily Load (TMDL), which would reduce the amount of phosphorous and other nutrients entering the lake, will be taken up by the Legislature next year. Iarrapino says this would be a good time to address the public health impacts of blue-green algae.
Although Vermont has a robust cyanobacteria monitoring program, which has served as a model for other states, it has always been hamstrung by a lack of resources. Indeed, the Department of Health’s reference guide to cyanobacteria states that there is “no state-wide program or federal funding available to address these local concerns.” Another document published by the monitoring team in 2010 notes that “Budget constraints are a serious issue.”
There are no plans to conduct a large-scale epidemiological study in Vermont.
“I think that would be the only way to look at public health impacts — to administer a large questionnaire,” says state toxicologist Vose. “We don’t have any plans in place to do that right now.”
Meanwhile, most scientists agree that the impacts of global climate change will only exacerbate the conditions that produce toxic algae blooms. Blue-green algae thrive in warm nutrient rich waters and respond especially well to high levels of phosphorous. In the wake of Tropical Storm Irene, which led to record high levels of phosphorous in the lake from storm runoff, algae blooms were particularly acute. In the summer of 2012, one year after the Hurricane, Kingsland Bay State Park and South Burlington’s Red Rocks beach were closed temporarily because of heavy blooms.
According to Lori Fisher, executive director of the Lake Champlain Committee, warmer temperatures associated with climate change as well as increased precipitation and runoff may be fueling blooms in a broader area of the lake.
“It reinforces the need to be even more aggressive about efforts to control nutrients,” she says.
Clarification: An earlier version of this story was unclear about the Lake Champlain Committee’s role in blue-green algae monitoring. It was updated Nov. 18, 2013.
