A second pond in Portsmouth has been closed this week due to blue-green algae.

The Rhode Island Department of Health (RIDOH) and the Rhode Island Department of Environmental Management (RIDEM) are advising people to avoid contact with St. Mary’s Pond in Portsmouth because of blue-green algae (or cyanobacteria) blooms in that pond. Blue-green algae can produce toxins that can harm humans and animals.

Earlier this week, Melville Pond was closed for a similar issue. Melville Pond remains closed at this time.

People should not ingest untreated water or eat fish from St. Mary’s Pond. Because pets can be affected by exposure to algal toxins, owners should not allow pets to drink this water or swim in the water. This advisory will remain in effect until further notice.

Contact with water containing cyanobacteria can cause Irritation of the skin, nose, eyes, and/or throat. If water containing algal toxins is ingested, health effects can include stomach ache, diarrhea, vomiting, and nausea. Young children and pets are at greater risk than adults, due to their size and because they are more likely to drink contaminated water. Other health effects, which are rarer, include dizziness, headache, fever, liver damage, and nervous system damage. People who have been swimming in, or have otherwise been in contact with, St. Mary’s who experience symptoms should contact their healthcare providers.

Anyone who comes into contact with water from St. Mary’s should rinse their skin with clean water as soon as possible, bathe, and wash their clothes. If a pet comes in contact with this water, the pet should be washed with clean water. Do not let the animal lick algae off of its fur. Call a veterinarian if the pet shows any symptoms of blue-green algae poisoning, which include loss of energy, loss of appetite, vomiting, diarrhea, or any unexplained sickness that occurs within a few days of contact with the water.

Note that St Mary’s Pond is a drinking water source maintained by Newport Water. Newport Water’s primary goal is to provide safe drinking water for all of its customers. As the main drinking water supplier for the residents of Newport, Middletown, and Portsmouth, Newport Water serves nearly 70,000 people Even when a cyanobacteria bloom is present in a pond, the treated water that Newport Water distributes to homes is safe. Treatment removes harmful bacteria, including cyanobacteria, before the water is delivered to customers.

Newport Water follows all state and federal drinking water testing and monitoring requirements to assure that treatment processes are working correctly and the water is safe to drink. Drinking untreated water from any pond at any time is not recommended.

Water that is treated to become drinking water comes from nine different surface reservoirs or ponds: St. Mary’s Pond, Sisson Pond, Lawton Valley Reservoir, South and North  Easton Ponds, Gardiner Pond, and Paradise Pond located on Aquidneck Island, Nonquit Pond in Tiverton, and Watson Reservoir in Little Compton – all owned and maintained by Newport Water. While RIDOH and RIDEM are now issuing a public health advisory for St. Mary’s Pond, Newport Water’s other water supply ponds also routinely experience blue-green algae (cyanobacteria) blooms.  Most algae blooms occur in the summer and fall, but they can occur at any time of year.

Newport Water needs all residents and visitors on Aquidneck Island and in Tiverton and Little Compton to help protect these valuable drinking water supplies. State law prohibits both people and animals from swimming and bathing in ponds that are drinking water sources. In addition, Newport Water prohibits fishing, swimming, and boating in these reservoirs, as posted.

Cyanobacteria blooms also occur in other waterbodies in the State. The public should avoid contact with any body of water in Rhode Island 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.

To report suspected blue-green algae blooms, contact DEM’s Office of Water Resources at 222-4700 or DEM.OWRCyano@dem.ri.gov.