High Toxic Algae Levels Found In Charles River, Health Advisory Issued

BOSTON, MA —Officials have issued a Public Health Advisory after high levels of cyanobacteria, also known as blue-green or toxic algae, were found in the Lower Basin of the Charles River this week.

The Charles River Watershed Association first said in a Tuesday morning Facebook post that they noticed the high levels of cyanobacteria in the lower basin. The following day, they shared an update saying that the Department of Public Health visited the site but was not yet issuing a bloom advisory.

Late Thursday afternoon, the Charles River Watershed Association officially posted an advisory for the area of water downstream of the Longfellow Bridge.

The DPH declared the body of water unsafe for people and pets, warning visitors not to swim or swallow water and to keep animals away and rinse off after any contact with the water.

Cyanobacteria occur naturally in freshwater ecosystems but can reach excessive levels when the biological condition of the water results in high nutrients but low dissolved oxygen, according to the United States Environmental Protection Agency.

"Although there are relatively few documented cases of severe human health effects, exposure to cyanobacteria or their toxins may produce allergic reactions such as skin rashes, eye irritations, respiratory symptoms, and in some cases gastroenteritis, liver and kidney failure or death," the EPA said.