Stay Out Of The Charles River: Toxic Blue-Green Algae, E. Coli

CHARLESTOWN, MA — The red flags flying along the Charles River between the Mass Ave Bridge and the Charles River Dam are to warn people or their pets against touching the river.

The Charles River Watershed Association issued the cyanobacteria, also known as blue-green algae, advisory Wednesday.

"It is recommended that you avoid contact with the water," according to the advisory. "People should rinse off with fresh water immediately if they or their pet comes into contact with the water."

The association recommends if you believe you or your pet are experiencing adverse health effects, to contact your doctor or veterinarian immediately.

"Blue-green algae is extremely toxic to pets," they said.

Because of the recent rainfall, the association is also asking residents to be cautious of possible E. coli bacteria in the stretch of the river from the Newton Yacht Club to Harvard’s Weld Boathouse. Stormwater runoff can wash pollutants and bacteria into the river, harming water quality.

Read the advisory here.