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New Hampshire Department of Environmental Services

Media Center

DATE: August 14, 2009
Jody Connor (603) 271-3414 or 419-9229
Sonya Carlson (603) 271-0698

State Issues Cyanobacteria Warning for Cobbett’s Pond, Windham

Concord, NH – An elevated cyanobacteria cell concentration has been measured in Cobbett’s Pond, Windham. Samples revealed that the state standard of 50% or greater of the total cells from the bloom were identified as the cyanobacteria Anabaena circinalis. As a result, the New Hampshire Department of Environmental Services (DES) has issued a cyanobacteria warning for those who recreate on Cobbett’s Pond. This warning is not based on a toxin evaluation and is intended as a precautionary measure for short term exposure. DES advises lake users to avoid contact with the water in areas experiencing elevated cyanobacteria cell conditions typically where lake water has a blue-green surface scum or swirls. DES also advises pet owners to keep their pets out of any waters that have a surface scum or blue-green swirls.

Lake users should be on the lookout for cyanobacteria surface scums. The current bloom is variable with some lake portions free of scum sightings while other areas have large blue-green scums and swirls in the water. Recent sightings report congregations of the blue-green clumps near the Windham Town Beach.

DES routinely monitors public beaches and public waters of the state for cyanobacteria. DES monitors public waters issued cyanobacteria warnings 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 ranging in severity from skin and mucous membrane irritations, nausea, vomiting, and diarrhea to liver and central nervous system damage for humans and animals.

The August 14, 2009 warning will remain in effect until additional samples reveal cyanobacteria levels have diminished.

Visit the DES Beach Program website at photos and more information about cyanobacteria. Updates on advisories and warnings may be obtained at

If you notice anything resembling cyanobacteria, please refrain from wading, swimming, or drinking the water. Keep all pets out of the water and contact DES immediately. Please call DES to report a cyanobacteria bloom at (603)419-9229.

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NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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