On June 27, 2017 a team from the Mystic River Watershed Association (MyRWA) collected water samples at nine locations along the Mystic River system as part of an ongoing effort to screen for harmful cyanobacteria blooms.
Of the nine samples screened, six--from the Mystic River and Upper Mystic Lake--showed evidence of elevated levels of phyocyanin, the photosynthetic pigment in cyanobacteria.
Additional testing by the Massachusetts Department of Public Health (DPH) confirmed high cell counts in the Mystic River near Blessing of the Bay in Somerville, in excess of state thresholds for posting health advisories. A health advisory was posted in Somerville, urging people to avoid ingestion or prolonged contact with the water for people and pets.
MyRWA will continue to screen samples throughout the summer. We will work with state and local departments of public health to report the results of any follow-up testing and to help publicize any health advisories.