On July 5, 2017 MyRWA staff collected water samples at eight sites along the Mystic River to test for evidence of cyanobacteria blooms. Six of the locations tested positive for phyocyanin, the photosynthetic compound in blue-green algae.
Testing by the Massachusetts Department of Public Health (DPH) confirmed that there were cyanobacteria cell counts above state thresholds in the Mystic River near Blessing of the Bay in Somerville and in Upper Mystic Lake. Shannon Beach on Upper Mystic Lake has been closed as a result of these findings, and the public is urged to avoid ingestion or prolonged contact with the water for people and pets. See the DPH website for more information.