Bloomin' river: Now is really a good time to not jump into the Charles

The state Department of Public Health yesterday confirmed that the Charles River from the Longfellow to the dam is now full of blue-green algae, which means you need to be especially careful to keep your dogs and young children out of it, the Charles River Watershed Association reports.

Cyanobacteria, or blue-green algae, are naturally occurring microorganisms in rivers, lakes and ponds that can potentially release harmful cyanotoxins, exposure to which can be fatal to pets and young children. Direct contact with cyanobacteria-contaminated water can cause skin rashes, and inhaling airborne toxins can affect respiratory systems, especially for those with pre-existing conditions like asthma.

Due to these severe health risks, DPH has deemed the area unsafe for people and pets and has advised the public not to swim or swallow water in the area, to keep their pets away and to rinse off after having contact with the water.

It's the first such bloom in that stretch of the river in four years, the association says, and is based on data from an EPA buoy near the Museum of Science that tracks various river conditions, including substances that can indicate the presence of blue-green algae:

The association sued the EPA in federal court in 2022 to try to get it to make cities and towns along the Charles better filter stormwater runoff to reduce the amount of phosphorus - which promotes the growth of the microorganism in the Charles. The case is still pending.