MERRIMACK — Officials have issued a health advisory warning citizens about contaminated water at Horseshoe Pond.
Extensive clouds of cyanobacteria have been discovered in the pond, prompting the New Hampshire State Department of Environmental Services to warn residents who may swim or wade in the water.
“DES advises lake users to avoid contact with the water in areas experiencing a surface scum or blue-green clouds,” says a news release issued by state officials. “DES also advises pet owners to keep their pets out of water that has a surface scum or blue-green clouds.”
Samples recently collected from the pond tested positive for coelosphareium, anabaena, spirulina, microcystis and oscillatoria, which are all capable of producing toxins harmful to humans and pets, according to the warning.
Symptoms may include skin irritation, mucous membrane problems, nausea, vomiting and diarrhea, as well as damage to the liver and central nervous system, according to the warning.
“This warning is intended as a precautionary measure to prevent short-term exposure to cyanobacteria toxins, and is not based on a toxin evaluation,” the release says.
DES will continue to monitor Horseshoe Pond on a weekly basis until the cyanobacteria bloom is no longer evident. The warning, however, will remain in effect until additional water samples are taken in about a week.
In the meantime, health officials are urging anyone who notices cyanobacteria to refrain from wading, swimming or drinking the water at Horseshoe Pond, a popular fishing spot in town.
A similar warning was issued last week for Province Lake in Effingham, where cyanobacteria bloom was discovered at the boat launch on Bonnyman Road and along Point, Bailey and Remick roads.