Forget about that swim in the Charles River Basin

The Charles River Watershed Association reports the Charles from the Weld boathouse to the dam now has high enough levels of toxic cyanobacteria to post warnings against coming into contact with river water - and that means no swimming, fishing or falling in the river. That goes double for dogs, who could pick up toxic residue in walks on the river banks and then lick it off their fur.

This is the same microorganism that shut Jamaica Pond to recreational use last month. The association blames a combination of low water levels and fertilizer runoff into the river for the bloom of cyanobacteria.

According to U.S. EPA, the relationship between high phosphorus levels from storm water discharges to the Charles and the proliferation of cyanobacteria is well-established. Studies show that phosphorus, a nutrient which cyanobacteria require to grow, is present in the Charles at more than twice the levels the river can safely handle. This phosphorus, carried into the river by stormwater runoff flowing over impervious surfaces, including roads, parking lots and roofs, and discharged via storm drains, causes cyanobacteria and invasive aquatic plants to grow explosively, smothering and shading other aquatic organisms.