State Removes Cyanobacteria Advisory for Harvey Lake in Northwood, New Hampshire
The New Hampshire Department of Environmental Services (NHDES) has REMOVED a cyanobacteria advisory for Harvey Lake that was issued on 8/9/2021. Cyanobacteria advisories are issued when cell concentrations exceed 70,000 cells/ml. Samples collected on 8/30/21 contained Dolichospermum, Woronichinia and Microcystis with cell concentrations ranging from 15,000 to 25,000 cells/ml. However, a few reports of surface accumulations have still been noted this week. While the surface bloom has mostly dissipated, NHDES advises that lake-goers look out for clouds and surface accumulations in the future. 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 August 9, 2021 and was removed on September 3, 2021.