The Rhode Island Department of Health and Department of Environmental Management are advising people to avoid contact with three waterbodies, including Upper Melville Pond in Portsmouth, because of harmful algae blooms.

The advisory also applies to Wenscott Reservoir in North Providence and Wilson Reservoir in Burrillville. Water samples were collected by DEM and tested by the Health Department’s State Health Laboratories, and initial samples at all three locations exceeded the advisory threshold.

All recreation, including swimming, fishing, boating and kayaking, is considered high risk and should be avoided at the affected waterbodies, the agencies said. The blooms are caused by blue-green algae, also known as cyanobacteria, which are naturally present in bodies of water but can produce toxins harmful to humans and animals.

Officials urged caution in all areas of the three waterbodies, as blooms can move locations within ponds and lakes. People should not drink untreated water or eat fish from the affected waters, and pet owners should not allow pets to drink or swim in them. The advisory remains in effect until further notice, with follow-up samples to be collected to confirm the water is safe before it is lifted.

Skin contact with water containing the blooms can cause rashes, sore throat and irritation of the eyes and nose, while swallowing the water can cause stomachache, diarrhea, vomiting and nausea. More serious but less common effects may affect the liver and nervous system or cause irregular heartbeat, dizziness or seizures. Young children, pets and people who are immunocompromised or have certain underlying health conditions may be at greater risk.

Anyone who comes into contact with a bloom should rinse their skin with clean water right away and shower and wash their clothes afterward. Pets exposed to the water should be washed immediately and kept from licking algae from their fur, and a veterinarian should be called if a pet shows signs of illness such as tiredness, loss of appetite, vomiting or diarrhea within a day. People who feel sick after contact should call a healthcare provider.

Officials said affected waters may show bright to dark green scum along the shoreline, with thick algae floating on the surface resembling green paint, pea soup or green cottage cheese. People and pets should avoid any water that looks like this.

Suspected blooms can be reported to DEM’s Office of Water Resources at DEM.OWRCyano@dem.ri.gov or by calling 401-222-4700. More information and a Cyanobacteria Tracker Dashboard listing current advisories are available at dem.ri.gov/bluegreen.