By SENTINEL STAFF
Granite State News Collaborative
ALSTEAD, N.H. — The N.H. Department of Environmental Services issued a cyanobacteria warning for Warren Lake in Alstead last Wednesday.
Another Monadnock Region body of water, Lake Monomonac in Rindge, has been under a similar warning since late last month. The state issued another warning for the lake on Thursday.
Water samples collected Wednesday at Warren Lake show cyanobacteria concentrations as high as 197,000 cells per milliliter. The state issues advisories when those concentrations rise above 70,000 cells per milliliter. Warnings are issued when the blooms are present at concentrations where toxin production is likely.
Lake Monomonac’s cyanobacteria levels were as high as 76,600 cells per milliliter as of Thursday, according to the state.
The state advises people and pets to avoid water with elevated cyanobacteria levels, also known as blooms. Lake-goers should continue to monitor the shoreline of the affected bodies of water, since blooms can change rapidly.
Cyanobacteria occur naturally in water bodies around the world, and blooms and surface scum can form due to excess nutrients, according to the state environmental agency. Some cyanobacteria produce toxins that can cause a variety of acute and chronic health issues.
Photos of cyanobacteria blooms, and more information, are available at des.nh.gov/water/healthy-swimming/harmful-algal-blooms. People can get updates on advisories at des.state.nh.us/WaterShed_BeachMaps/.
Potential cyanobacteria blooms can be reported at 603-848-8094 or [email protected].
These articles are being shared by partners in the Granite State News Collaborative. For more information, visit collaborativenh.org.
