The state's cyanobacteria advisory for the Charles River running through Needham and Dedham remains in effect as of Monday, July 27, with laboratory test results not yet returned after an expected Friday, July 25, deadline passed.
The Massachusetts Department of Public Health issued the advisory on Tuesday, July 22, warning residents and pet owners to stay out of the river between Kendrick Street/Nahanton Street (Needham/Newton) and Bridge Street/Spring Street (Dedham/West Roxbury). The Town of Needham formally posted the warning on Friday, July 24. The affected stretch includes Millennium Park and Cutler Park Reservation.
State officials collected water samples on Thursday, July 23, to test for cyanobacteria cells and cyanotoxins. Results were expected the following day. As of July 27, no results have been published and the advisory remains active, according to the Needham town website and Patch reporting.
What prompted the advisory
MDPH issued the warning after receiving a report that a dog died from liver failure following possible exposure to algal toxins near Millennium Park. The dog, a 16-year-old mixed breed named Dobby, belonged to Elivia Savadier Sagov of West Roxbury. Dobby swam in the river on Saturday, July 18, and died two days later on Monday, July 20, according to GBH News.
State officials have not confirmed that cyanobacteria caused the dog's death.
Why clear water doesn't mean safe water
What makes this bloom unusual is that it grows along the river bottom, not on the surface. Marielena Lima, river science program manager for the Charles River Watershed Association, told NBC Boston that the water can appear clear even when dangerous.
"I've heard anecdotes from the dog owner saying, you know, the water looked clear, and that is possible with benthic cyanobacteria blooms," Lima said.
Julie Wood, climate resilience director for the Charles River Watershed Association, told GBH News on July 22 that prolonged drought and high temperatures have created conditions favorable for this type of growth. She said benthic mats like these are unprecedented in her experience tracking cyanobacteria on the Charles.
What residents should do
The advisory instructs residents to:
- Avoid all contact with the water
- Not swim, boat, fish, or drink the water
- Keep pets away from the river
- Rinse off immediately if water contact occurs
Warning signs are posted at access points along the affected stretch.
Children and pets are especially vulnerable because of their smaller body size, according to the Boston Public Health Commission. Pet owners whose animals have been near the river should contact a veterinarian immediately if they notice vomiting, excessive drooling, loss of coordination, staggering, or seizures.
Residents with questions can contact the Needham Public Health Division at 781-455-7940 or [email protected]. MDPH maintains a beach water quality dashboard at mass.gov/dph/algae where residents can check for updates on the advisory status.
