The Boston Public Health Commission issued a health advisory Friday warning the public to avoid contact with the water in the Charles River downstream from the Massachusetts Avenue Bridge due to a toxic algae bloom.
The city said the bloom was discovered after staff at the state Department of Public Health identified the presence of cyanobacteria that exceeds DPH guidelines for recreational waterbodies in the state.
Paul Shoemaker, director of the Environmental and Occupational Health Division at the Boston Public Health Commission, said he received notification and immediately put out the alert.
“There’s an overgrowth of cyanobacteria, or what’s sometimes called blue-green algae, in the water,” he said. “People are advised to avoid contact with the water and to keep children and pets away from the water.”
He added that coming in contact with the algae can make people sick.
“The algae in the water can release what’s called a cyanotoxin, which can be harmful. It can cause gastrointestinal upset, nausea, vomiting, diarrhea, all those unpleasant health symptoms, which can be very serious, particularly for small children and pets,” he said.
The alert system, according to Shoemaker, depends on community organizations, individuals, and state agencies that keep an eye on the various surface waters in the state, including the Charles River. If they notice the green paint-like color along the surface of the water, which looks almost like pea soup, inspectors take a sample to test for an algae bloom.
Marielena Lima, the River Science Manager at the Charles River Watershed Association, was out doing surveillance Wednesday and saw the very green, hazy water in the Charles River Lower Basin firsthand.
“We do monitoring at two different sites along the Cambridge area,” she said. “One is by the Broad Canal, a Paddle Boston rental site area, and then the other one is at Poor Man’s Landing, which is a dock just on the Cambridge side, and both areas were very, very green,” Lima said.
In July, West Roxbury resident Elivia Savadier Sagov said her dog died of liver failure two days after swimming in the Charles River at Millennium Park. Sagov suspected an algae bloom could be to blame, but DPH tested the waters two days later after a heavy rain, and found levels of cyanobacteria below the threshold levels that produce toxins that can make people and pets sick.
Lima said the CRWA does cell counts when they see what looks like a bloom present in the water.
“Last week at Poor Man’s Landing, we actually did have a sample that was over that threshold, so we came back this week to kind of confirm that, and the water was looking much greener, and the cell counts were even higher, so it is definitely — we are in a bloom,” she said.
DPH requires two rounds of samples collected a week apart that are below the threshold of 70,000 cells per milliliter of water to determine that the advisory can be lifted.
DPH will conduct sampling for laboratory analysis once the bloom has dissipated.
Health effects for people and pets that come in contact with blue-algae producing toxins can include issues with the functioning of the liver, kidneys, and/or neurological systems. In severe cases toxins produced by blue-green algae can result in death. Pet owners are advised to call their veterinarian immediately if their dog has been around an algae bloom and shows symptoms such as vomiting, staggering, drooling, or convulsions. The symptoms present themselves soon after exposure.
Harmful algae blooms are most common in the summer months when warm sunny conditions promote algae growth.
The best way to stop algae bloom growth is to reduce phosphorus pollution in the Charles River, such as fertilizers and collecting leaves that have nutrients in them that feed the algae.
A state website includes an updated list of all bodies of water with algae bloom advisories.
Lima said signs are posted about the alert, and the CRWA works to educate the public when a bloom is present. She said there was a bloom in the same area last year.
“Every single presentation or anything, we do try to make sure people know about cyanobacteria blooms, the possible dangers of being exposed to water with blooms in it,” she said. “And it is becoming more of a consistent, recurring event each summer.”
