For Immediate Release

Wednesday, July 12, 2017

Media Contact: John Guilfoil
Phone: 617-993-0003
Email: john@jgpr.net

Arlington Health Officials Issue Warning after High Levels of Cyanobacteria Found in Upper Mystic Lake

ARLINGTON — Public Health Director Natasha Waden reports that high levels of cyanobacteria (blue-green algae) were detected in the Upper Mystic Lake during a recent water sampling conducted by the Massachusetts Department of Public Health (DPH).

DPH collected the sample from a portion of the lake in Winchester last week, following a report from a resident that algae had bloomed in the body of water. Arlington officials received notification of the high levels of cyanobacteria on Monday night.

Cyanobacteria algae grows naturally beneath or on the surface of many bodies of water. Under certain conditions (like warm weather and an abundance of nutrients in the water), the algae may experience a significant amount of growth that results in dense, floating mats of it throughout the water. This is commonly referred to as an “algae bloom.”

This particular type of algae can be toxic if ingested in high doses and can cause skin irritation and a rash after wading or swimming. The Arlington Board of Health strongly advises residents not to swim or stand in the water and urges pet owners to keep their animals away from the water.

Contact with high levels of the cyanobacteria algae has been found to contribute to eye, ear and skin irritation. During an algae bloom, the amount of algae and toxin in the water can become elevated and exposure can be potentially harmful to people and animals. Ingestion of elevated concentrations of the algae and its toxin can lead to more serious health effects (i.e. muscle cramps, twitching and liver damage).

“To prevent sickness and skin irritation, we strongly advise community members and those with pets to avoid contact with Mystic Lake,” Waden said. “‘We will be monitoring this situation closely and will let the public know as soon as it’s safe to resume activities in the lake.”

DPH will continue to collect samples on a weekly basis until cell counts drop to safe levels, at which point the Arlington Board of Health will notify the community.

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