Update as of 8/28/2019 per Lake Health Committee: We were informed that DES has lifted the cyanobacteria warning from Halfmoon Lake and it is now safe to swim there (Dalton and Crescent beaches). However, the green algae is still present in Locke Lake and should be avoided.
Original Posting Date per Lake Health Committee: 8/22/2019 Have you noticed green surface scum on Locke Lake? Avoiding contact is recommended The New Hampshire Department of Environmental Services (NHDES) reported August 21, 2019 a green algae bloom along the shorelines and coves of Locke Lake. The bloom appeared as bright green surface scums, similar to that of cyanobacteria. While the bloom contained mostly green algae, a few colonies of cyanobacteria were also found mixed in with this bloom. The levels of cyanobacteria were not elevated enough to issue an advisory, however, contact with water in areas experiencing the bloom should be avoided. 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. Both the Colony’s Lake Health Committee and NHDES have been closely monitoring this situation. Samples have been taken daily over the last 3 days and sent to DES.
As of 8/28/2019 HALFMOON LAKE ADVISORY HAS BEEN LIFTED HALFMOON LAKE ADVISORY IN EFFECT On Halfmoon Lake, a cyanobacteria advisory went into effect on August 20, 2019 and will remain in effect until NHDES confirms that cell concentrations of the bloom have subsided. This advisory is not based on a toxin evaluation and is intended as a precautionary measure for short term exposure. NHDES will return weekly until the cyanobacteria standards are again met. NHDES advises lake users (people and pets) to avoid contact with the water in areas experiencing elevated cyanobacteria cell conditions.
REPORT YOUR CONCERNS and PASS THIS INFORMATION TO YOUR VISITORS AND RENTERS If you notice anything resembling cyanobacteria, please call NHDES at (603) 848-8094.
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