This story is based on information from the N.H. Department of Environmental Services and the Conway Daily Sun.
Freedom—August 31, 2018—As Labor Day weekend begins, a cyanobacteria warning remains in effect for Danforth Pond, according to the N.H. Department of Environmental Services.
The blue-green algae of a cyanobacteria bloom is seen on Danforth Pond. DES photo.
As a precaution, swimmers should avoid the blue-green algae scum patches and colored flecks that have been found along the pond’s shoreline and coves. Pets should also be kept away from the blooms.
The blooms were reported on August 24 and sampled by the state on August 29. A previous warning was posted for Danforth on August 15 and lifted on August 22. Earlier this summer, cyanobacteria was detected in Berry Bay near the dam but quickly dissipated.
Cyanobacteria are natural components of water bodies that can trigger unsightly blooms when there is an excess of nutrients in the water. Since the blooms may or may not produce harmful toxins, the state errs on the side of caution when issuing warnings. Recreational exposure can result in nausea, vomiting, diarrhea and skin and mucous membrane irritation.
Excess nutrients in lakes are often caused by fertilizers. The NH Shoreland Protection Act prohibits the use of fertilizer closer than 25 feet from shore. Between 25 and 250 feet from shore, only low phosphate, slow release nitrogen fertilizer may be used. Failed or leaking septic systems can also result in nutrients leaching into lakes and rivers.
Cyanobacteria is monitored by the state’s Beach Inspection Program. Click here for more on the program or for information on how to report cyanobacteria blooms. Updated information on warnings is available on Twitter at this link.