State REMOVES Cyanobacteria Advisory for Long Pond in Henniker, NH

Concord, NH - The New Hampshire Department of Environmental Services (NHDES) has REMOVED a cyanobacteria advisory for Long Pond that was issued on 7/16/2020. Samples have been collected weekly by New England College and Henniker Conservation, and analyzed by NHDES. Samples collected on 8/30/2020 revealed that the bloom has currently dissipated and no cyanobacteria cells were found at the beach or at the surface. Few cells of Planktothrix were observed deeper in the lake but at low concentrations of 10,000 cells/ml. While the bloom has dissipated, NHDES advises that lake-goers look out for surface accumulations in the future. Please continue to monitor your individual shoreline for changing conditions.

This advisory was not based on a toxin evaluation and was intended as a precautionary measure for short term exposure. Cyanobacteria are natural components of water bodies worldwide, though blooms and surface scums may form when excess nutrients are available to the water. Some cyanobacteria produce toxins that are stored within the cells and 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, tingling, numbness, nausea, vomiting, seizures and diarrhea. Chronic effects may include liver and central nervous system damage. Be cautious of lake water that has a surface scum, changes colors, or appears to have green streaks or blue-green flecks aggregating along the shore.

The advisory went into effect on July 16, 2020 and was removed on September 1, 2020.