From MCPPC Montgomery Parks (http://www.montgomeryparks.org/)
Visitors Urged to Use Caution and Avoid Ingesting Water at Lake Needwood and Lake Frank Due to Elevated Microcystin Levels
UPDATE: Microcystin, a toxic substance produced by blue-green algae (cyanobacteria), has been detected in Lake Needwood and in Lake Frank. Water that contains microcystin can cause severe liver damage if ingested. Please avoid all contact with the lake water, and do not allow dogs or other pets to swim in or drink from the lake. Swimming is prohibited at all times in Lake Needwood and Lake Frank. Fishing is allowed, but visitors are urged to use good hand cleaning practices prior to eating, drinking, or smoking. If eating fish caught from Lake Needwood or Lake Frank, visitors should eat only muscle meat and ensure that the fish is cooked properly. For more information, please call 301-495-259
More Information
Rockville Patch: http://rockville.patch.com/groups/around-town/p/warning-lake-bernard-frank-is-contaminated
Centers for Disease Control and Prevention Fact Sheet: http://www.cdc.gov/hab/cyanobacteria/pdfs/facts.pdf