Suffolk County health officials are advising that people stay out of Maratooka Lake because of blue-green algae blooms.
The Suffolk County Department of Health Services said Thursday that the presence of blue-algae blooms, or cyanobacteria blooms, in the Mattituck lake has been confirmed by Stony Brook University.
Exposure to the blooms can cause nausea, vomiting, diarrhea, skin or throat irritation, allergic reactions or breathing difficulties, according to the New York State Department of Environmental Conservation.
Blue-green algae can also produce toxins that affect the liver and nervous systems when water is consumed in sufficient quantities.
Blue-green algae is naturally present in lakes and streams in low numbers, but when they become abundant, blooms in shades of green, blue-green, yellow, brown or red are formed. Floating scum may form on the surface or the water may take on a paint-like appearance, the agency said.
Contact with waters that appear scummy or discolored should be avoided. If contact does occur, rinse off with clean water immediately.
The DEC also has confirmed blue-green algae in Lake Ronkonkoma and in Lake Agawam in Southampton and in Big Reed Pond in Montauk and in Mill Pond near Yaphank.
Report a suspected blue-green algae bloom in a Suffolk beach by calling the Suffolk County Department of Health Services at 631-852-5760. For bodies of water outside Suffolk, call the New York State Department of Environmental Conservation at 518-402-8179.