SPOFFORD — The N.H. Department of Environmental Services will collect water samples from Spofford Lake Wednesday after the discovery of what may be a type of bacteria never before seen in New England, according to an official with the state agency.
The department issued an advisory Thursday after lake volunteers alerted officials of a black smudge-like substance in the water, according to Amanda McQuaid, harmful algal and cyanobacterial bloom program coordinator at the department. The advisory against wading and swimming in the lake will remain in effect until the department can determine the water is safe.
People should likewise stay out of the water at Ware’s Grove and North beaches until further notice, according to a post on the Chesterfield Parks and Recreation Department’s Facebook page.
The bacteria in question is thought to be Lyngbya wollei, a strain of cyanobacteria. While cyanobacteria, also called blue-green algae, is quite common in New Hampshire, this particular strain has never been found in New England, McQuaid said.
However, she said, it’s still undetermined whether Lyngbya wollei is indeed the strain of cyanobacteria in Spofford Lake.
“It is quite possible that it is not wollei, we would need further confirmation using DNA methods. However, it is characteristic of it,” McQuaid, who will be collecting the water samples Wednesday, said in an email.
“There are thousands of different types of cyanobacteria and hundreds of toxins,” she added.
Lyngbya wollei appears on the surface of lakes and is very dark in color. This strain, like other forms of cyanobacteria, can sometimes be caused by certain nutrients and warm temperatures, McQuaid said.
Lyngbya wollei is typically found in Florida, she said, but has also been seen in the Great Lakes and Canada.
Adverse reactions to the bacteria occur when too much is ingested, she explained. For humans, symptoms range from rashes, nausea and vomiting to long-term liver and central nervous system damage.
The bacteria is more worrisome for pets, McQuaid noted, as they are more likely to consume large quantities of lake water.
If the bacteria in Spofford Lake is determined to be Lyngbya wollei, McQuaid said it will be difficult to clean out.
“Unfortunately, it can be more toxic to try to get rid of them as they occur,” she said. “The cyanobacteria can release toxins which can sometimes create a more toxic situation.”
There are certain ways to prevent the bacteria, such as reducing nutrients, but McQuaid said it can often be unpredictable. She added that many short-term solutions to get rid of the bacteria can be harmful to the lakes in the long run.
“It is best to let them cycle out naturally,” she said.
The N.H. Department of Environmental Services’ advisory says people should be cautious of lake water with a surface scum, that changes colors or that has green streaks or blue-green flecks collecting near the shore.