Toxic Algae Bloom Closes Pennington Lake

PENNINGTON, NJ — Rosedale Lake in Pennington was closed Tuesday after a harmful algae bloom was discovered, according to the Mercer County Parks Commission. It's the third lake in New Jersey to experience the bloom, which is toxic to humans and animals.

Cyanobacterial Harmful Algal Blooms, or HABs, have also affected Lake Hopatcong and Spruce Run in recent weeks.

The harmful algae blooms happen when cyanobacteria overproduces in a body of water. In the right situations – such as sunlight, hot and calm waters and high nutrients – the bacteria can cause a bloom that's toxic to humans and animals.

The blooms are fairly common in North Jersey lakes, but it is unusual to see the blooms this early in the season, the Department of Environmental Protection says.

While the lake was closed to all recreation, the playgrounds, trails, dog park and picnic area remain open, the Mercer County Parks Commission said.

See more on Patch:

• Harmful 'Cyanobacteria' Shuts Down Swimming At Several NJ Sites
• All Of Lake Hopatcong Closed To Swimming Due To Algae
• Two Lake Hopatcong Beaches Closed After Algae Bloom
• Lake Hopatcong's Terrible Summer: Algae Blooms Could Ruin Season

The DEP says the blooms often look like pea soup or like a layer of bright blue/green or white paint on the water surface.

Exposure to the bacteria can cause rashes, allergy-like reactions, flu-like symptoms, skin and eye irritation, and gastroenteritis. Several people have reported suffering skin rashes after coming into contact with lake water, officials said.

See the DEP's information sheet for pictures of the algae blooms.

Swartswood State Park was closed in June due to a harmful bloom, but was later reopened once the bloom subsided.