BELCHERTOWN — A potentially harmful algal bloom in Lake Metacomet has officials recommending residents stay out of the water until the growth clears.
“Basically, I’m advising people to avoid or minimize contact with the water,” said Erica Cross, Belchertown’s conservation administrator. “Boating and fishing are safe, but you want to minimize time spent in the water.”
Cross explained that a combination of warm water temperatures, slow-moving water and excess nutrients make for environments ripe for bacterial growth. She suspects the bloom is a form of cyanobacteria based on the frothy, blue-green appearance.
She says under no circumstances should anyone touch the bacteria with bare skin, as it could be toxic. Extra precautions should be taken not to let children or pets ingest the water.
Chul Park is an associate professor in the department of civil and environmental engineering at the University of Massachusetts who specializes in the study of algae and microbial processes.
“Usually algal blooms are caused by an increase in temperature, most importantly by the imbalance of nutrients, especially nitrogen a phosphorous,” Park said. “With increasing temperatures, we tend to see more events of harmful algal blooms.”
He said the blue-green algae blooms have potential to be toxic, but are not always.
“Even if you see them growing in the water that does not mean they are producing toxins,” Park said. “Under very limited conditions and environmental distress they produce toxins; it is not very well known why.”
Chemical tests can determine the toxicity of a specific type of bacteria, but before that is confirmed Park says lake recreationists should exercise caution. If toxic, touching the algae with bare skin can cause rashes or irritation, Cross said.
Nutrients in the form of nitrogen and phosphorous can come from a variety of sources like leaking septic systems, lawn fertilizer, stormwater or agricultural runoff. Globally, blooms of cyanobacteria are on the rise as warmer temperatures, driven by climate change, hasten the growth. Last year, Florida’s governor declared a state of emergency and beaches were closed when algae blooms spread from Lake Okeechobee to nearby estuaries, and more than 100 people fell ill after swimming in Utah’s largest freshwater lake.
“Generally speaking, if we see their concentration elevating it generally causes concern,” Park said.
Park recommends identifying the point source of the nutrient overload and stopping it there, instead of removing just the bacteria. One potential source, he said, could be any wastewater treatment facilities releasing water upstream, as the cleansing process removes pollutants, but not the phosphorus and nitrogen found in organic materials.
“If there are a lot of septic systems in the town so these nutrients can eventually leach out into groundwater, which will eventually enter into the lake water,” Park said. “We also know these days more nitrogen enters from the atmosphere too.”
To combat the problem in the long term, Cross said the town is working to get more people connected to the town sewer system instead of using septic tanks, and increase flow through the lake. Near-drought conditions in Belchertown have not helped matters, she said.
“Reducing nutrients is the best we can do,” Cross said. “We can’t do anything about global warming, but we can maintain flow through our Tri-Lake area.”
Sean Gallagher, president of the Tri-Lakes Association, said members of the organization took down three beaver dams on Sunday to restore water flow through the lake.
He said in some areas the water was close to 85 degrees, warmed by the intense heat wave earlier this month. He described the situation as a “bacteria frappe.”
“It has been seen by some neighbors,” Gallagher said. “We have some folks looking to scoop it up.”
Lakeside residents can fight the algal bloom by skimming the growths off the surface of the water and disposing of them away from the water body.
Cross recommends wearing protective gear — rubber gloves, long sleeves, pants and eye cover — before handling the algae, which she says makes for excellent composting.
“It has fabulous nutrients for any compost pile,” Cross said.
Large algae blooms, when left to grow, can use all the nutrients available in the water, cause hypoxic conditions from lack of oxygen, and create an unsavory living situation for other aquatic creatures. In extreme cases, mass fish die-offs can result from unchecked algal blooms.
Algae blooms are especially common in small ponds and lakes that get warm in the summer while water levels are low and stagnant, Park said.
“Once this starts happening, it’s quite difficult to control, so it may need some kind of comprehensive understanding of the sources,” Park said.
Sarah Robertson can be reached at firstname.lastname@example.org.