Harmful Algal Bloom at Chebacco Lake

October 2020

Reports of Harmful Algal Blooms have abated with the cooler weather.  No further testing will occur this year for Cyanobacteria.


Monday August 31, 2020

When in Doubt, Stay Out!

The MA Department of Public Health will conduct testing for Cyanobacteria toxin at only one location, Centennial Grove Beach, after no visible signs of algae are present at the beach.  No other area of Chebacco Lake will be tested.

Please visit the Essex Board of Health webpage to see the status and results of the tests.

Link here for: More information about Harmful Algal Blooms


Monday August 24, 2020

When in Doubt, Stay Out!

Link here for drone view: Video Chebacco Lake, Gregory Island, August 21, 2020



Friday August 21, 2020

Beware Swimmers, Boaters, and Dogs

Hamilton Board of Health is advising swimmers, boaters, and dog owners to beware of the dangers of Harmful Algal Blooms.  This photo was taken at the shore of Gregory Island, on Chebacco Lake, observed earlier this week and confirmed today.

Link here for: Photo at Chebacco Lake, Gregory Island, August 17-21, 2020

Link here for: More information about Harmful Algal Blooms


On Friday July 24, 2020 we received confirmation from the Massachusetts Department of Public Health’s Environmental Toxicology Program that there is a harmful algal bloom (HAB) of cyanobacteria in Chebacco Lake at Centennial Grove.

During the following week the Hamilton Board of Health received a report of a small patch (size of a platter) of algae in Echo Cove seen on 7/24/20.

We ask the public to be vigilant before entering the water at Chebacco Lake, or any fresh water body.  Please notify the Board of Health if an algal bloom is suspected.  If possible, please take pictures and email to: [email protected] and [email protected]. Please provide contact info of the person who observed, and the size, date and location where the suspected HAB was observed.

Link here for: Photos taken 7/23/20 at Chebacco Lake in Essex.

Health concerns associated with CyanoHABs vary depending on the type of cyanobacteria, the route of exposure, and the amount of cyanotoxins present. Ingestion is the primary concern since ingesting small amounts of cyanobacteria or cyanotoxin can cause gastrointestinal symptoms while larger amounts may cause liver or neurological damage. Contact with cyanobacteria can cause skin or eye irritation. Inhaling water spray containing cyanobacteria can cause asthma-like symptoms. Small children and pets are more susceptible to the effects of cyanotoxins than adults.

Link here for: More information about Harmful Algal Blooms