Cyanobacteria, also known as blue-green algae, grow naturally in many water bodies. When certain conditions are present, such as warm weather and an abundance of nutrients in the water, the algae may undergo an explosive type of growth that is sometimes called an algae bloom. These blooms look like mats or thick paint on the surfaces of water. Blooms frequently appear blue or green but sometimes appear brown or red. These blooms can be harmful to people and animals.
Contact with cyanobacteria can cause skin and eye irritation. Ingesting small amounts can cause gastrointestinal symptoms. Ingesting large amounts may cause liver or neurological damage. Small children and pets are more susceptible to the effects of cyanobacteria than adults. Dogs, in particular, can get very ill and even die from ingesting cyanobacteria, either by directly ingesting it or licking it off their fur.
The Rhode Island Department of Health and the Rhode Island Department of Environmental Management work cooperatively to monitor the state’s lakes and ponds to detect the presence of cyanobacteria blooms and to advise the public of health concerns. The Department of Environmental Management’s Office of Water Resources monitors lakes with reported blooms and lakes that have historically had high nutrient and/or chlorophyll a levels (factors that lead to blooms). The agencies jointly issue Health Advisories when any of the following three criteria, which indicate that a bloom exists, are met:
Health advisories remain in effect for the remainder of the swimming season, unless follow-up sampling by a city, town, or third party indicate that the advisory can be lifted. Health Advisories may be lifted after two successive and representative sampling rounds, two weeks apart, demonstrate no evidence of an algal scum or mat and demonstrate cyanobacteria cell counts and toxin levels below threshold concentrations.
|Body of water||City or town||Year(s)||Dominant cyanobacteria species|
|Melville Pond||Portsmouth||2010||Anabaena, Microcystis|
|Almy Pond||Newport||2010||Aphanizomenon, Microcystis, Anabaena|
|Central Pond||East Providence||2010, 2007||Microcystis|
|Turner Reservoir||East Providence||2010, 2007||Microcystis|
|Lower Ten Mile River||East Providence||2007||Microcystis|
|Omega Pond||East Providence||2007||Microcystis|
|Yawgoo Pond||South Kingstown||1998||N/A|