A type of algae that can cause skin rash, eye irritation, and gastrointestinal problems has bloomed in part of the Charles River.
A bloom of cyanobacteria, or blue-green algae, has been found in the lower Charles River in the area of the Longfellow Bridge. The Massachusetts Department of Public Health issued an advisory Thursday recommending people and pets avoid contact with the water if it appears bright green or contains bright green strands.
Blue-green algae is commonly found in Eastern Massachusetts and the Charles River, but large quantities of the algae can cause various health problems for humans and animals because of a toxin the dying algae secretes, according to the Charles River Watershed Association, which helps monitor the river and uses a daily water quality flagging program.
The algae blooms when there are warm temperatures, sunlight, and excess nutrients in the river--often caused by runoff. Heavy rainstorms followed by hot weather can lead to severe blooms in the Charles, the association explained on its website.
The toxins produced by the bacteria can cause rash, nose, eye, or throat irritation,
stomachaches, diarrhea, and vomiting if the water comes directly in contact with a person's skin or if the water is ingested. Animals can also be affected by the toxins.
While visible green strands can show a high concentration of the algae, the association states that the toxins can remain in the water up to three weeks after a bloom is no long visible.