Sisson Pond Portsmouth

The Rhode Island Department of Health (RIDOH) and the Rhode Island Department of Environmental Management (RIDEM) are lifting the remaining blue-green algae advisories for bodies of water in Rhode Island. Recent visual surveys of locations under advisory found that there were no blooms of blue-green algae, also known as cyanobacteria.

Advisories are lifted for the following bodies of water:

  • Little Compton: Watson Reservoir
  • Middletown: Gardiner Pond
  • Newport: Almy Pond
  • Portsmouth: Sisson Pond
  • Providence: Mashapaug Pond, Roger Williams Park (Japanese Gardens, Roosevelt Lake) 
  • Portsmouth: Melville Ponds

These improvements were expected due to seasonal cooling and declining daylight, and they signal a great reduction in risk. However, there is no guarantee that toxins are absent, or that a warm spell might not trigger a bloom during the winter/spring season. Seasonal monitoring for cyanobacteria in 2018 is finished, but the public is reminded to avoid contact with any body of water that is bright green or has a dense, floating algal mat on the water’s surface. Blue-green algae blooms may look like green paint or thick pea soup.  Toxins may persist in the water after a blue-green algae bloom is no longer visible.

Contact with water containing blue-green algae toxins can cause irritation of the skin, nose, eyes, and/or throat. Ingestion of water containing blue-green algal toxins can cause stomach ache, diarrhea, vomiting, and nausea. Other health effects, which are rarer, include dizziness, headache, fever, liver damage, and nervous system damage. Young children and pets are at greater risk than adults, due to their size and because they are more likely to drink contaminated water.

People who experience the symptoms associated with blue-green algae exposure and who have been swimming or fishing in water or drinking untreated water from a waterbody with a confirmed or suspected cyanobacteria bloom, should contact their healthcare providers. People who come into contact with potentially affected waters should rinse their skin and wash their clothes with clean water as soon as possible. People observing pets exhibiting adverse health symptoms after contact with potentially affected waters should contact their veterinarians. Pets who encounter potentially affected waters should not be allowed to lick water off their fur and should be rinsed with clean water as soon as possible.
To report suspected blue-green algae blooms, contact DEM’s Office of Water Resources at 222-4700 or    


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