The Rhode Island Department of Health (HEALTH) and the Department of Environmental Management (DEM) are advising people to avoid recreational activities in Slacks Reservoir in Johnston and Smithfield. The reservoir's water had a visible scum of cyanobacteria in a cove in the upper eastern part of the reservoir, near Greenlake Town Beach in Greenville. These blue-green algae, typically referred to as cyanobacteria, have the potential to form the naturally occurring algal toxins known as Microcystin and Anatoxin.
Individuals should avoid all contact with water in Slack Reservoir, including recreational activities such as swimming, boating, or fishing. People should not eat fish from this reservoir. Pets can also be affected by exposure to algal toxins and should not be allowed to wade or swim in, or drink water from this reservoir.
The toxins can cause harm to humans and animals. Skin rashes and irritation of the nose, eyes, and/or throat are common side effects that result from skin contact with water containing algal toxins. If water containing algal toxins is ingested, health effects include stomach ache, diarrhea, vomiting and nausea. Young children and pets are more at risk to algal toxins than adults, since 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 drinking from, swimming, or fishing in these areas and experience those symptoms should contact their healthcare provider. People observing pets exhibiting adverse health symptoms after contact with water from this reservoir should contact their veterinarian.
People and pets that come into contact with the water should rinse their skin with clean water as soon as possible, and wash their clothes. People are cautioned that toxins may persist in the water after the blue-green algae bloom is no longer visible.
Warm temperatures and sunshine produce conditions favorable to algae growth. DEM and HEALTH warn that blue-green algae blooms may be evident in other freshwater lakes and ponds in the state. People are advised to avoid contact with waters that exhibit the following conditions: 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.