Community Corner

Toxic Algae That Can Harm Humans, Pets Found In 2 County Lakes

Park officials are urging residents to take precautions after a toxic algae was found in two Montgomery County lakes.

Park officials are urging residents to take precautions after a toxic algae was found in two Montgomery County lakes.
Park officials are urging residents to take precautions after a toxic algae was found in two Montgomery County lakes. (Shutterstock)

ROCKVILLE, MD — A toxic algae that, if ingested in large quantities, can cause liver damage in pets and people has been spotted in two Montgomery County lakes. It has prompted local park officials to issue a fresh warning about the dangers of swimming in these bodies of water.

Elevated levels of microcystin, a toxic substance produced by some species of blue-green algae (cyanobacteria) were detected at Lake Needwood and Lake Frank, according to Montgomery Parks. Both lakes are located within Rock Creek Regional Park.

"Of particular concern are dogs that are off-leash and may swim and/or drink from the lake, despite park regulations," Montgomery Parks said in a statement.

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Samples have been sent to the Maryland Department of the Environment for testing. The results should come back next week, officials said.

Swimming is prohibited at these lakes, but you can still take your boat out or fish. You just need to be very cautious, officials said.

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"Signs have been posted around Lake Needwood and Lake Frank and along trails that access the lakes to ensure visitors are aware of the elevated levels of microcystin, and to urge visitors to take precautions," said Rock Creek Regional Park Manager Mike Jones. "Portions of both lakes may be contaminated for the rest of the season. We will continue to monitor and update signs when the warning is lifted."


Montgomery Parks is urging residents to take the following precautions:

  • Avoid direct contact with water while boating or fishing
  • Keep dogs on leash (as is regularly required at the park), and do not allow them to drink or be in contact with the water
  • Wash hands thoroughly prior to 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


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