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New Hampshire Department of Environmental Services

Media Center

DATE: June 8, 2011
CONTACT: Jody Connor (603) 271-3414 or 419-9229
Sonya Carlson (603) 271-0698
Teresa Ptak (603) 271-8803

State Issues Cyanobacteria Lake Warning for Jenness Pond, Northwood

Concord, NH – An elevated cyanobacteria cell concentration has been measured in Jenness Pond, Northwood. Samples revealed that the state standard of 50% or greater of the total cells from the bloom were identified as the cyanobacteria Microcystis. As a result, the New Hampshire Department of Environmental Services (DES) has issued a cyanobacteria lake warning for those who recreate on Jenness Pond. The current bloom is variable with some lake portions free of elevated cell conditions while other areas have small blue-green clouds in the water. Recent sightings report congregations of the blue-green clouds within both First and Loon Cove. 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. 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, clouds or flecks. DES also advises pet owners to keep their pets out of any waters that have these conditions.

DES routinely monitors public beaches and public waters of the state for cyanobacteria. Once a cyanobacteria lake warning has been issued, DES 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 June 8, 2011 warning will remain in effect until additional samples reveal cyanobacteria levels have diminished.

Visit the DES Beach Program website for photos and more information about cyanobacteria at
Updates on advisories and warnings may be obtained at
Follow the Beaches twitter feed:

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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