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New Hampshire Department of Environmental Services

Media Center

DATE: June 19, 2020
CONTACT: Amanda McQuaid (603) 271-0698 (O), 848-8094 (C)

State REMOVES Cyanobacteria Advisory for Baboosic Lake in Amherst/Merrimack, NH

Concord, NH- The New Hampshire Department of Environmental Services (DES) has REMOVED a cyanobacteria advisory for Baboosic Lake that was issued on 06/17/2020. Cyanobacteria were identified as Anabaena (Dolichospermum), Oscillatoria and Woronichinia. Cell concentrations were 516,000 cells per milliliter of lake water at the beach. Advisories are issued when cyanobacterial cell concentrations exceed 70,000 cells/ml. Samples collected on 6/19/2020 revealed that the bloom has currently dissipated and few cells of cyanobacteria were observed.

Resampling is typically conducted weekly since blooms tend to move around the lakes with wind and currents. Upon inspection on 6/19, water appeared clear at the main beach. Though cyanobacteria were still suspended throughout the water column. The chances for a bloom to accumulate along shorelines are still likely. While the bloom has mostly dissipated, NHDES advises that lake-goers look out for green surface accumulations in the future. Periodic blooms may recur in this water body and people should still be on alert. Please continue to monitor your individual shoreline for changing conditions.

This advisory was not based on a toxin evaluation and was intended as a precautionary measure for short term exposure. 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.

The advisory went into effect on June 17, 2020 and was removed on June 19, 2020.

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

If you notice anything resembling cyanobacteria, please refrain from recreating in bloom water and DO NOT drink the water. Keep pets and children out of the water and contact NHDES immediately. Call NHDES to report a cyanobacteria bloom at (603) 848-8094 or email

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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