Effingham — July 1, 2018 — The New Hampshire Department of Environmental Services has removed a cyanobacteria lake warning at Berry Bay on Ossipee Lake on the Effingham Freedom border.

The warning went into effect on June 22 and was removed on Friday. Samples collected on June 22 revealed that the state threshold of 70,000 cells per milliliter or greater of cyanobacteria was exceeded.

The cyanobacteria were identified as Anabaena/Dolichospermum from a bloom accumulating near the dam in Effingham (about 170,000 cells/ml).

The Volunteer Lake Assessment Program collected additional samples on Tuesday. Anabaena, Merismopedia and Aphanocapsa were identified in very low quantities.

No further blooms have been observed in this area at this time.

Cyanobacteria are natural components of water bodies worldwide, but blooms and surface scums may form when excess nutrients are available to the water.

Some cyanobacteria produce toxins that are stored within the cells that can be 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 include liver and central nervous system damage.

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, green streaks or blue-green flecks aggregating along the shore. NHDES also advises pet owners to keep their pets out of any waters that have a cyanobacteria bloom.

NHDES routinely monitors public beaches and public waters of the state for cyanobacteria. Once a cyanobacteria lake warning or beach advisory has been issued, NHDES returns to affected water bodies on a weekly basis until the cyanobacteria standards are again met.

Visit the NHDES Beach Program website for photos and more information about cyanobacteria at tinyurl.com/nhlakebloom.