Blue-Green Algae Blooms Resurface In Harford, Baltimore, Charles, Kent And Cecil County Waters
Citizens Urged to Use Caution When Recreating
BALTIMORE, MD — The Maryland Departments of Natural Resources, Health and Mental Hygiene, Agriculture and Environment today advised Marylanders to take precautions when swimming, boating or recreating in certain waterways this summer as blue-green algae blooms have been positively detected in various waterways around the state.
Current surveys show that blue-green algal blooms, dominated by Microcystis, Anabaena and Aphanizomenon have been observed along the Bush River, Harford County; Frog Mortar Creek of Middle River, Baltimore County; in the Potomac River at Mattawoman Creek and Sandy Point, Charles County; and the Sassafras River, Kent and Cecil Counties.
Blue-green algae naturally occur in tidal freshwater portions of the Chesapeake Bay and its tributaries. However, algal blooms may periodically deplete oxygen from waterways, causing fish to suffocate and die. Heavily affected waters may also appear as if bright green paint is floating on the surface of the water blocking light to aquatic vegetation. Major blue-green algae blooms were last reported in the region in 2000 and 2003.
Although there have been no confirmed cases this year of human illness, pet or livestock deaths linked to blooms, people should take common precautions to reduce the risk of illness or discomfort if they come in contact with algae blooms.
- The public should not swim in areas where a blue-green algae bloom is evident. Do not drink water from any area with appearance of a blue-green algae bloom. Some strains of Microcystis, Anabaena and Aphanizomen produce toxins; gastrointestinal discomfort, headache, diarrhea and potential liver damage may occur from ingesting concentrated blue-green algal bloom waters.
- If contact is made with problem water, simply wash off with fresh water. In some cases, skin irritations and rashes may occur after prolonged contact. If irritations persist, see a physician or local health care provider.
- Keep pets and livestock away from bloom areas. Blue-green algal blooms may contain a toxin that could be harmful or fatal to pets and livestock. Environmental conditions may be appropriate for the development of blooms in other freshwater parts of the Chesapeake Bay and the tributaries as the summer progresses.
- Internal organs (innards) of fish caught in bloom waters should not be eaten. Caution should be taken regarding consumption of fish taken from waters where major blue-green algal blooms occur.
In hot weather, and especially in still water with high levels of nutrients, blue-green algae can grow and accumulate rapidly, causing a “bloom.” The excess nutrients and poor flushing in the Chesapeake Bay and its tributaries contribute to these types of conditions.
Algae are a natural and critical part of our Chesapeake and Coastal Bays ecosystems. Algae, like land plants, capture the sun’s energy and support the food web that leads to fish and shellfish. They occur in a size range from tiny microscopic cells floating in the water column (phytoplankton) to large mats of visible “macroalgae” that may float on the surface or grow on aquatic vegetation and bottom sediments.
Algae may become harmful if they occur in an unnaturally high abundance or if they produce a toxin. A high abundance of algae can block sunlight to underwater bay grasses, consume oxygen in the water leading to fish kills, produce surface scum and odors, and interfere with the feeding of shellfish and other organisms that filter water to obtain their food. Some algal species can also produce chemicals that are toxic to humans and aquatic life. Fortunately, of the more than 700 species of algae in Chesapeake Bay, less than 2% of them are believed to have the ability to produce toxic substances. Six water samples have been collected from the algal bloom locations and sent to Wright State University for cyanotoxin testing, results are pending.
Cyanotoxins like microcystin can bioaccumulate in common aquatic organisms like fish and mussels. The levels of accumulation vary based on several factors and require more investigation.
A fact sheet on Microcystis and the 2003 bloom conditions can be found on the Department of Natural Resources website at: http://www.dnr.maryland.gov/bay/hab/microcystis2.html To report human illness from bloom water contact or consumption, a fish kill or fish health-related event, call the Maryland Aquatic Health Hotline at (888) 584-3110, 24 hours a day.
Posted June 11, 2004