Health Advisory: Cyanobacteria Algae in the Charles River

Avoid Contact with Water Downstream of Massachusetts Avenue/Harvard Bridge

The Cambridge Public Health Department is alerting residents of a cyanobacteria algae bloom in the Charles River downstream of Massachusetts Avenue and the Harvard Bridge. This includes Broad Canal, Lechmere Canal, North Point Park, Lederman Park, Community Boating docks, and Storrow Lagoon (see map above). Residents are urged to avoid contact with the water and any areas where there is visible algae. 

The Charles River downstream of the Harvard Bridge is temporarily closed to water activities. While this closure is in effect, individuals should not:   

• Swim, fish, boat, jet ski, or engage in other recreational activities on/in the water
• Consume fish from this area  
• Allow dogs to swim in or drink the water  

Algae and cyanobacteria (also called blue-green algae) are plant-like organisms that live in water. They can quickly grow out of control, or “bloom.” Some of these blooms produce toxins (poisons) that make people and animals sick. If you, your child, or your pet comes in contact with the water, rinse off immediately. Contact can cause skin and eye irritation, and inhalation or ingestion can cause respiratory irritation and other illness. If the blue-green algae are producing toxins, the health effects can be serious.  More information about illnesses caused by harmful algal blooms can be found on the CDC website.

Harmful algal blooms can be deadly for animals. Contact a veterinarian immediately if your pet seems sick after going in or near water. Animals can get very sick or even die within hours of coming into contact with harmful algae or cyanobacteria. Learn more about protecting pets.

 How long will this health advisory be in effect?   

The Massachusetts Department of Public Health (DPH) will continue to monitor cyanobacteria algae levels in this area and will conduct sampling of the water for analysis. The advisory will be lifted after two rounds of samples collected a week apart indicate that algae are no longer at levels that are considered unsafe.    

More information about harmful algal blooms can be found on the DPH’s website.