Montgomery Co. warns of toxic algae at Rock Creek Regional Park

There are signs that toxic algae is contaminating at least one Montgomery County lake, and officials are warning visitors to use caution around the water.

Montgomery Parks said in a release Saturday there are obvious signs of a blue-green algae that produces microcystin on the surface of Lake Needwood. Microcystin is a toxic substance that can cause liver damage to pets and people if ingested in high concentrations. Samples of the algae have been sent to the Maryland Department of the Environment for testing and results are expected next week.

In the mean time, signs have been posted around both Lake Needwood and Lake Frank, both in Rock Creek Regional Park, to alert visitors.

Park officials said they’re especially concerned about dogs drinking from or swimming in the lakes, and said all dogs should stay on leash and avoid all contact with the water.

Montgomery Parks is also urging visitors to follow these precautions:

  • Avoid direct contact with the water while boating or fishing
  • Swimming is prohibited in the lakes at all times
  • Wash hands thoroughly before eating, drinking, or smoking if someone comes in contact with the water
  • Only eat properly cooked muscle meat of fish that are caught in the lake

Recreational activities such as boating and fishing will remain open at the lake.

Microcystin was first found at Lake Needwood in 2009, and testing has been done regularly ever since. The toxic algae was also found in both Lake Needwood and Lake Frank last year.

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