Toxic algae is back, this time on the Cape

The Association to Preserve Cape Cod has an interactive map and other resources on its website that allow people to better understand cyanobacteria blooms on the Cape.

It’s that time of the year.

At least two Cape Cod ponds have posted advisories regarding algae blooms.


As of Sunday, people and pets were warned not to swim or ingest water in any way from the Mashpee-Wakeby Pond due to a cyanobacteria bloom.

“Waterbody is unsafe for people and pets; do not swim, do not swallow water, keep animals away, and rinse off after contact with the water,” an advisory on the Mashpee town website reads, adding that any questions can be directed to the Mashpee Board of Health or the Mashpee Department of Natural Resources.

Some climate change factors that could contribute to algae blooms include warm water temperatures, sea level rise, changes in rainfall and salinity, and higher carbon dioxide levels, according to the U.S. Environmental Protection Agency.


Barnstable officials posted an advisory about cyanobacteria on its social media pages Wednesday. The post noted that of the approximately 150 ponds that the Association to Preserve Cape Cod monitors, about one-third have recently had elevated levels of cyanobacteria.

The APCC has an interactive map and other resources on its website that allow people to better understand cyanobacteria blooms and where to watch out for them on the Cape.

On June 13, APCC identified a potentially toxic cyanobacteria bloom at Bearses Pond in Barnstable, The Cape Cod Times reported.

Ingesting significant amounts of cyanobacteria can lead to “skin irritation, neurological impairment and organ impairment,” APCC Executive Director Andrew Gottlieb told the newspaper.

In Sandwich, town officials released a video last week, detailing how they plan to look for and respond to algae blooms.

“Last year, we had a lot of issues with cyanobacteria and we were doing testing with cyanobacteria, which we will not be doing this year,” David Mason, town director of public health, said in the video, which was recorded at Peters Pond and posted to the town’s YouTube page on June 22.

“We know cyanobacteria is in the pond,” he said. “We already know it, and testing cyanobacteria isn’t mandated by state law.”


Instead, Mason said town officials will be monitoring the situation this year by checking the status of the ponds each morning, training lifeguards on what they need to know about algae blooms, and posting advisories at the ponds, as needed.

The ponds will, however, be tested weekly for E. coli, which is required by law, Mason said, adding that residents will only be notified of the levels in the event that ponds are forced to close.

“We’ve had very few closures for E. coli for the past few years, so we’re not expecting a concern with that,” he said.

Guy Boucher, recreation director, and Dave DeConto, director of natural resources, also spoke in the video, detailing the status of lifeguards at each pond in town.

The full video can be found below:

More information on algae blooms can be found on the Centers for Disease Control and Prevention website.


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