|Algal bloom at Harvard's Weld Boathouse. Photo by CRWA|
Alert issued by MA Department of Public Health
The malodorous toxins can contribute to minor health impacts such as eye, ear, and skin irritation, or have more severe consequences for humans or their pets ranging from liver and neurological damage to death. People and pets should avoid contact with or ingestion of water with high concentrations of cyanobacteria, and river bank areas where the bacteria have washed up. If contact occurs, individuals should rinse off as soon as possible following exposure. Dogs can become quite ill and even die from contact with cyanobacteria scum. They should be prevented from licking cyanobacteria out of their fur and rinsed off immediately. Inhaling water spray containing cyanobacteria can cause asthma-like symptoms. Because wind and flow patterns can affect the location of the bloom, all recreational users of the Charles River Lower Basin should take precautions. State and local officials will be posting signs along this stretch of the Charles advising river users of the bloom.
Low river levels with elevated water temperatures, hot sunny weather, and high phosphorus concentrations from polluted stormwater runoff provide the ideal environment for rapid growth of cyanobacteria and harmful toxin levels. 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.
“Until municipalities and owners of large paved surfaces dramatically reduce their phosphorus runoff, these outbreaks will continue to harm the Charles and people’s enjoyment of this tremendous resource,” said Bob Zimmerman, CRWA’s Executive Director. “It is far past time for EPA and MassDEP to issue new stormwater permits to reduce these polluted discharges.”
Cyanobacteria blooms are becoming increasingly common in the Charles River during the summer months. A bloom in early June caused the Charles River Swim Club’s 1-mile race in the Lower Basin near the Memorial Hatch Shell to be postponed until July. Last summer, a toxic cyanobacteria bloom in Lake Erie shut down the drinking water supply for more than 400,000 Toledo area residents.