Concord, NH – An elevated cyanobacteria cell concentration has been measured in Hopkinton-Everett Lake at the Elm Brook Park Beach in Hopkinton. Samples revealed that the state threshold of 70,000 cells / ml or greater of cyanobacteria was exceeded. The cyanobacteria were identified as Anabaena and Woronichinia. As a result, the New Hampshire Department of Environmental Services (NHDES) has issued a cyanobacteria advisory at the beach area for those who recreate at Elm Brook Park Beach. The heaviest bloom areas were observed near the boat ramp and appear either as a scum on the surface or small blue-green clumps suspended in the water column. Please continue to monitor your individual shoreline for changing conditions.
This warning is not based on a toxin evaluation and is intended as a precautionary measure for short term exposure. NHDES advises lake users to avoid contact with the water in areas experiencing elevated cyanobacteria cell conditions typically where lake water has a surface scum or blue-green flecks. NHDES also advises pet owners to keep their pets out of any waters that have a surface scum or blue-green or bright green flecks.
NHDES routinely monitors public beaches and public waters of the state for cyanobacteria. Once a cyanobacteria warning has been issued, NHDES returns to affected waterbodies on a weekly basis until the cyanobacteria standards are again met. Cyanobacteria are natural components of water bodies worldwide, but blooms and surface scums may form when excess phosphorus is available to the water. Some cyanobacteria produce toxins that are stored within the cells but released upon cell death. Toxins can cause both acute and chronic health effects that range in severity. Acute health effects include irritation of skin and mucous membranes, nausea, vomiting, and diarrhea. Chronic effects include liver and central nervous system damage.
The warning went into effect on June 19, 2017, and will remain in effect until additional samples reveal cyanobacteria levels have diminished.