Two Natick Ponds Contain Possibly Harmful Algae, Health Officials Warn

NATICK, MA - State and local health departments are advising people not to swim at two Natick ponds because of the detection of a potentially harmful blue-green algae called cyanobacteria found in the water earlier this week.

According to the town's Health Department website, the state's Department of Conservation and Recreation found visual evidence on Wednesday of a cyanobacteria bloom in the South Pond of Lake Cochituate and Fiske Pond. Cyanobacteria are microscopic organisms that occur naturally in lakes and streams. Lake Cochituate runs through Natick, Framingham and Wayland.

Warning signs are being posted at access points along the ponds advising people not to swim in the water and to prevent pets from entering or swallowing the water.

Exposure to high levels and their toxins can cause diarrhea, nausea and vomiting, as well as skin, eye and throat irritation and breathing difficulties. Small children and pets are more susceptible to symptoms. High levels of exposure can cause liver damage and affect the nervous system.

Cyanobacteria blooms occur in freshwater bodies, according to the state's Bureau of Environmental Health. Blooms can have the appearance of paint or pea soup and can emit a foul odor. Sometimes cyanobacteria can be dispersed throughout the water, while it can also concentrate on the water's surface or near the shoreline.

Warm water, sunlight and stagnant water conditions can contribute to the growth of cyanobacteria. It can also cause skin and eye irritation.

The town's health department advised those exposed to rinse off after contact with the water.

DPH will return to conduct follow-up water sampling when there is no longer any visual evidence of a bloom.