PORTSMOUTH — The R.I. Department of Health (RIDOH) and the R.I. Department of Environmental Management (RIDEM) are advising people to avoid contact with seven waterbodies, including Sisson Pond in Portsmouth, because of potential risks from blue-green algae.

Blue-green algae can produce toxins, including microcystins, that can harm humans and animals.

All recreation, including swimming, fishing, boating, and kayaking, should be avoided, the two agencies stated in an Aug. 9 press release. People should not ingest water or eat fish from these waters. Pets can also be affected by exposure to the algal toxins and thus owners should not allow pets to drink or swim in the water. The advisory remains in effect until further notice.

Sisson Pond is a drinking water source maintained by Newport Water, the main drinking water supplier for the residents of Newport, Middletown and Portsmouth, serving 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, according to RIDOH.

“Treatment removes harmful bacteria, including cyanobacteria, before the water is delivered to customers,” stated the press release. “Newport Water follows all state and federal drinking water testing and monitoring requirements to assure that treatment processes are working correctly and the treated water is safe to drink.”

Drinking untreated water from any pond at any time is not recommended, according to the press release. “Newport Water may deliver treated drinking water from nine potential surface reservoirs or pond sources including: 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. While RIDOH and RIDEM are now issuing a public health advisory for Sisson Pond, Newport Water's other water supply ponds also routinely experience blue-green algae (cyanobacteria) blooms,” according to the press release.

Newport Water needs all residents and visitors on Aquidneck Island and in Tiverton and Little Compton to help protect those drinking water supplies, the state said. 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.

The other waterbodies that fell under the advisory are Almy Pond in Newport, JL Curran Reservoir in Cranston, Mashapaug Pond in Providence, and three lakes in Roger Williams Park in Providence.

Blue-green algae blooms may affect other waterbodies in Rhode Island. People are advised to avoid contact with waterbodies that exhibit bright green coloration in the water or at the water surface and/or dense floating algal mats that form on the water's surface. The water may look like green paint, thick pea soup, or green cottage cheese. Most algae blooms occur in the summer and fall, but they can occur at any time of year.

To report suspected blue-green algae blooms, contact DEM's Office of Water Resources at 401/222-4700 or DEM.OWRCyano@dem.ri.gov. If possible, send a photograph to accompany the reported condition.