Montgomery Parks urges patrons to use caution when recreating on or near Lake Needwood and Lake Frank located within Rock Creek Regional Park due to potential risks associated with high levels of blue-green algae (cyanobacteria). Water samples from both lakes are currently being evaluated by the Maryland Department of the Environment (MDE) to determine if levels are harmful. Visual indicators including discolored water and algal mats have been observed in portions of both lakes. Harmful Algal Blooms (HABs) can produce dangerous levels of toxic microcystin.
“As a precautionary measure, we are alerting the public of the risks associated with potentially high levels of cyanobacteria in these lakes,” said Matt Harper, natural resources manager with Montgomery Parks. “While we await the toxin testing results, we urge people to keep their dogs on leash and ensure they are not allowed contact with the water.” Park Rules and Regulations prohibit dogs from swimming in Montgomery Parks’ lakes.
Cyanobacteria are naturally occurring algae in the environment but can grow in excess and produce harmful toxins, including microcystin, a hepatotoxin. High concentrations of microcystin may harm humans and pets if ingested. Of primary concern are off-leash dogs that may swim and/or drink from the lake, despite park regulations. Montgomery Parks urges visitors to take the following precautions:
- Avoid direct contact with water while boating or fishing; swimming is always prohibited in lakes
- Keep dogs on leash (per park regulations), and do not allow them to drink or be in contact with the water or algal mats accumulating on shorelines
- If your pet has been in contact with lake water or algae, rinse fur with clean water and seek veterinary care if you are concerned
- Wash hands thoroughly before eating, drinking, or smoking if you have come in contact with the water
- Only eat properly cooked muscle meat of fish