State REMOVES Cyanobacteria Advisory for Forest Lake in Whitefield/Dalton, NH

Concord, NH - The New Hampshire Department of Environmental Services (DES) has REMOVED a cyanobacteria advisory for Forest Lake that was issued on 7/20/2020. Cyanobacteria advisories are issued when concentrations exceed 70,000 cells/ml. Cyanobacteria were identified as Anabaena/Dolichospermum. Several samples were collected on 7/29 and 7/30 and it is apparent that the bloom has dissipated. Most samples contained no cyanobacteria and very few cyanobacteria cells were found at all (250-1,250 cells/ml). While the bloom has dissipated, NHDES advises that lake-goers look out for green 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 20, 2020 and was removed on July 30, 2020.