DES release concerning Partridge Lake

News from the New Hampshire Department of Environmental Services



DATE: September 19, 2017

CONTACT:           David Neils (603) 271-8865, 848-8094 (C)


State Issues Cyanobacteria Warning for Partridge Lake, Littleton, NH


Concord, NH – An elevated cyanobacteria cell concentration has been measured in Partridge Lake, Littleton, NH.  Samples collected from the lake on September 17, 2017 revealed an estimated cell density 33,000 cells / ml of cyanobacteria. The cyanobacteria were identified as Anabaena (Dolichospermum). As a result, the New Hampshire Department of Environmental Services (NHDES) has issued a cyanobacteria warning for those who recreate on Partridge Lake. The current bloom is appearing as an green cloud and scum on the water. Please continue to monitor your individual shoreline for changing conditions as blooms can come and go quickly.


This warning is not based on a toxin evaluation and is intended as a precautionary measure for short term exposure. 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, clouds or blue-green flecks. NHDES also advises pet owners to keep their pets out of any waters that have a surface scum or blue-green or bright green flecks.


NHDES routinely monitors public beaches and public waters of the state for cyanobacteria. Once a cyanobacteria warning has been issued, NHDES 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 warning went into effect on September 19, 2017, and will remain in effect until additional samples reveal cyanobacteria levels have diminished.


Visit the NHDES 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 NHDES immediately. Please call NHDES to report a cyanobacteria bloom at (603) 848-8094.

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