People and animals need no longer avoid parts of the Charles River from fear of a cyanobacteria algae bloom, health officials said after a 33-day health advisory alert.
The algae and cyanobacteria are plantlike organisms that can grow quickly out of control in the water and produce toxins that make people and animals sick.
The advisory called Aug. 21 was expected to take at least a week to lift, as the Massachusetts Department of Public Health had to take two rounds of samples collected a week apart that indicate the algae are no longer at levels that are considered unsafe, officials said. Instead, on Aug. 27, officials announced the potentially dangerous bloom had expanded.
On Monday, the Massachusetts Department of Public Health collected follow-up samples at three locations in the Charles. Laboratory analysis showed cyanobacteria concentrations were below the department guidelines at all three locations, and the alert was ended.
The previous bloom lasted had 11 weeks, ending Oct. 28, while this one lasted 4.7 weeks.
When the blooms happen, it means no swimming, fishing, boating, jet ski use or other recreational activities on or in the water, no eating of fish from the affected area and no letting dogs swim in or drink the water. “Harmful algal blooms can be deadly for animals,” officials said. “Animals can get very sick or even die within hours of coming into contact with harmful algae or cyanobacteria.”
For people, 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. Information about illnesses caused by harmful algal blooms can be found on here.
