skip navigation
New Hampshire Department of Environmental Services
PUBLIC GOVERNMENT BUSINESS A to Z LIST

Media Center

FOR IMMEDIATE RELEASE
DATE: August 30, 2018
CONTACT: Amanda McQuaid (603) 271-0698 (O), 848-8094 (C)
des.nh.gov
twitter.com/NHDES

State REMOVES Cyanobacteria Lake Warning for Halfmoon Lake in Barnstead and Alton, NH

Concord, NH –The New Hampshire Department of Environmental Services (DES) has REMOVED a cyanobacteria lake warning issued on 8/16/2018. Volunteers of Halfmoon Lake have been monitoring this waterbody carefully. Periodic blooms were seen, appearing as stringy, green streaks in the water. Cyanobacteria were identified as Oscillatoria. These accumulations turned white, indicating cell death. Samples collected 8/23/2018 showed that cyanobacteria were still concentrated, but cells were decaying. The most recent samples were collected 8/30/18 from the Dalton Beach area. No cyanobacteria were observed in these samples. Communication with volunteers and lake residents has been ongoing. There have been few sightings of this bloom since the advisory was issued. Please continue to monitor your individual shorelines for changing conditions.

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 waterbodies on a weekly basis until the cyanobacteria standards are again met.

The warning went into effect on August 16, 2018, and was removed on August 30, 2018.

Visit the NHDES Beach Program website for photos and more information about cyanobacteria at www.des.nh.gov/organization/divisions/water/wmb/beaches/index.htm
Updates on advisories and warnings may be obtained at www4.des.state.nh.us/WaterShed_BeachMaps/WaterShed_BeachMaps.aspx
Follow the Beaches twitter feed:
twitter.com/NHDES_Beaches

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.




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

copyright 2017. State of New Hampshire