Press Release

BALTIMORE, MD (July 22, 2003) – Marylanders are urged to take precautions when utilizing certain waterways as blue-green Microcystis algae blooms are being reported by the Maryland Departments of the Environment and Natural Resources. Current surveys show that Microcystis blooms have been observed along tributaries of the Sassafras River on the Eastern Shore. As a result, the environmental health directors of Kent and Cecil counties were directed to post notice of the bloom along Turner’s Creek.

Environmental conditions may be appropriate for the development of blooms in other parts of the upper Chesapeake Bay as the summer progresses. In hot weather, and especially in still water with high levels of nutrients, blue-green algae can grow and accumulate rapidly, causing a “bloom.” Although there have been no reported cases of human illness, people should take common precautions to reduce the risk of illness or discomfort related to Microcystis:

  • The public should not swim in areas where blue-green algae bloom is evident. Do not drink water from any area with appearance of a blue-green algae bloom.
  • If contact is made with problem water, simply wash off with fresh water. In some cases, skin irritations may occur after prolonged contact. If irritations persist, see a physician or local health care provider.
  • Keep pets and livestock away from bloom areas. Microcystis blooms may contain a toxin that could be harmful or fatal to pets and livestock.

Blue-green algae naturally occur in tidal freshwater portions of the Chesapeake Bay and its tributaries. However, algal blooms may periodically use up oxygen, causing fish to suffocate and die. Affected waters may also appear as if a blue-green to yellow-green paint is floating on the surface of the water. Major blue-green algae blooms were last reported in the region in 2000.

A fact sheet on Microcystis and the 2000 bloom can be found on the Department of Natural Resources’ website at: To report a fish kill or fish health related event, call the Fish Health Hotline at (888) 584-3110, 24 hours a day.