The Suffolk County Department of Health Services has declared parts of Fresh Pond unsuitable for swimming.
Samples taken recently from the pond and sent to the New York State Department of Environmental Conservation (DEC) for analysis have revealed the presence of cyanobacteria, or blue-green algae blooms.
Swimming for people or pets can pose a risk to their health, according to the DEC.
The public has been notified about the risk. At the town landing off Lake Drive, signs from the county in English and Spanish are posted, reading:
“BLUE-GREEN ALGAE BLOOM ADVISORY
Blue-green algae blooms have been spotted in this water body.
• Don’t swim or wade near blooms.
• Keep children and pets away from blooms or scum.
• Rinse with clean water if exposed.”
According to the National Oceanic and Atmospheric Administration, the presence of “harmful algal blooms” (HABs) can produce “harmful effects on people, fish, shellfish, marine mammals and birds.”
The DEC stated last week that the HABs in Fresh Pond are in “small localized” areas, meaning “portions … may be clear and fully support recreational uses.”
Contact with algal blooms, according to the DEC, can produce symptoms including vomiting, nausea, diarrhea, skin, eye or throat irritation, allergic reactions and breathing difficulties.
Water samples were taken at the pond on July 8 by Peter Grand, a member of the town’s Water Advisory Committee and the Fresh Pond Neighbors Association, who then delivered them to the DEC. The neighbors association is a member of the New York State Federation of Lake Associations. Mr. Grand and another member, James Eklund, have been trained in sampling and processing of water as part of the Citizens Statewide Lake Assessment Program.
Mr. Grand said this was the third test done this summer of the pond and all three tests, aside from the HABs, “showed the water to be exceptionally clear.” He found two locations “where there were growths of algae. That’s what we sampled.”
In addition to untreated sewage from aged or malfunctioning septic systems, HABs can be the result, according to the DEC, of a combination of factors, including extended periods of still water, sunlight and high temperatures.