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RIDOH and RIDEM Blue-Green Algae Advisories: Recommend Avoiding Contact with all Waters at Roger Williams Park and Warwick Pond while Lifting Restrictions for Slacks Reservoir

The Rhode Island Department of Health (RIDOH) and the Rhode Island Department of Environmental Management (RIDEM) announce the placement of advisories to avoid contact with all water bodies in Roger Williams Park in Providence and Warwick Pond in Warwick, while lifting the advisory for Slacks Reservoir in Greenville (spans Smithfield and Johnston town lines). The health advisories are being issued for Roger Williams Park and Warwick Pond due to blue-green algae blooms. Blue-green algae, also known as cyanobacteria, can produce toxins that are harmful to humans and animals.

The advisory for Slacks Reservoir has been lifted due to confirmed absence of blue-green algae and cyanotoxin. Contact with and recreational activities on the Reservoir and associated Slack Pond Beach may resume. The advisory was put in place in July due to the presence of a blue-green algae bloom.

Because of the continued presence of cyanobacteria, health advisories remain in place for Sisson Pond, Melville Pond, and St. Mary's Pond in Portsmouth; Almy Pond in Newport; Spectacle Pond and Blackamore Ponds in Cranston, and Turner Reservoir in East Providence. Contact with water containing cyanobacteria can cause irritation of the skin, nose, eyes, and/or throat. Ingestion of water containing cyanobacterial 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.

The public is reminded to 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 (cyanobacteria) 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.

People who experience the symptoms associated with cyanobacteria 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 have come in contact with 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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