Potentially toxic blue-green algae bloom detected at Mill Creek in Water Mill

Suffolk County health officials are warning residents to stay away from Mill Creek in Water Mill after water sample testing detected the presence of new blooms of potentially harmful cyanobacteria.

Officials said the blue-green algae was found by Stony Brook University biologists, who took surface water samples. It is considered a health risk to residents who use, swim or wade in the waters.

Though blue-green algae is naturally present in lakes and streams, it becomes harmful when it blooms or becomes abundant. Some species of cyanobacteria produce toxins that can cause health problems in humans and animals, according to health officials.

Blooms can appear in shades of green, blue-green, yellow, brown or red, and at times produce floating scums on the surface or a paint-like appearance.

If contact does occur with scummy or discolored water, rinse off with clean water immediately, officials said.

Hazardous algae blooms can be active for up to two weeks and may be present in all or parts of a water body, the state Department of Environmental Conservation said.

Harmful algae blooms were detected in 26 Suffolk water bodies in 2023, the most ever affected in the county in a single year since the DEC began tracking blooms statewide in 2012.

To report a suspected blue-green algae bloom in Suffolk in water open to swimming, residents can contact the Suffolk County Department of Health Services’ Office of Ecology at 631-852-5760 or email scdhsweb@suffolkcountyny.gov.

Algae blooms found in bodies of water not open to bathing can be reported to the DEC at habsinfo@dec.ny.gov.