PELHAM — The state lifted a cyanobacteria warning placed on Long Pond last month.

Cyanobacteria cell concentration in Long Pond locations in Pelham, Dracut, Mass., and Tyngsboro, Mass., are now below the level of a public health concern, according to the New Hampshire Department of Environmental Services.

The warning was issued Sept. 6 after large masses of greenish-blue blooms were discovered in the northern end of the pond. Over half of the blooms were identified as the cyanobacteria known as Anabaena.

The warning was issued as a precautionary measure to prevent short-term exposure to cyanobacteria and the water was tested weekly until standards were met.

The DES routinely monitors public beaches and water for cyanobacteria.

The bloom occurs naturally in water bodies but can increase in areas when phosphorus is in the water. If a bloom or surface scum forms cyanobacteria can present a potential danger to people and pets.

Some cyanobacteria store toxins that are released from its cells upon death. Health effects range in severity and can include skin and mucus membrane irritation nausea, vomiting and diarrhea. Chronic effects can include liver and central nervous system damage.

jhanson@newstote.com