Water is Safe: Cyanobacteria warning removed

Staff photo by Adam UrQuhart On Tuesday, New Hampshire Department of Environmental Services officials removed the cyanobacteria warning that had been in place for the Nashua River at Mine Falls Park. Although some globs were observed, they determined the bloom has subsided enough to end the warning.

NASHUA – After testing four separate samples collected this month, officials with the New Hampshire Department of Environmental Services removed a cyanobacteria warning for the Nashua River at Mine Falls Park.

On Aug. 3, officials issued the warning about cyanobacteria, exposure to which can lead to nausea, seizures and central nervous system damage.

This portion of the river now meets state cyanobacteria standards, so the warning has been lifted. However, officials are asking people to continue monitoring their individual shorelines for changing conditions.

While collecting samples on Aug. 3, millions of cells of Oscillatoria were observed accumulating in this region of the river. Officials collected samples again the following week on Aug. 10, and saw it still contained high concentrations of these cyanobacteria, while observations made on Aug. 17 once again indicated large globs of cyanobacteria still present.

According to the U.S. Environmental Protection Agency, cyanobacteria were previously known in some circles as blue-green algae. The modern scientific definitions of algae and bacteria led to the name change.

Finally, by Monday, a river sample revealed that the cyanobacteria bloom was dissipating, and although some globs were still observed, they determined the bloom has subsided.

Blooms and surface scums can form when excess nutrients are available to the water, and some cyanobacteria produce toxins that are stored within the cells that can be released upon cell death. Those toxins can then cause a range of health effects that vary 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.

State officials ask residents to report a potential cyanobacterial bloom at 603-848-8094.