Toxic blooms of green-blue algae have been found in Maryland lakes, but so far, none have been found in Frederick County waters.

The blue-green algae, also called cyanobacteria, have been in the news recently due to their harmful effects to dogs that swallow them. And while there are no blooms in Frederick County, other counties, including neighboring Montgomery County, have reported them.

There are normally around four to six advisories a year, said Jay Apperson, deputy director of communications for the Maryland Department of the Environment. There have been two so far. Microcystis is the most common.

Lake Waterford, in Anne Arundel County, had an advisory in July. Lake Needwood and Lake Frank in Montgomery County received one this week.

Two lakes in Frederick County — Lake Anita Louise and Lake Merle — have cyanobacteria in them, but the levels are below the World Health Organization guidelines, Apperson said in an email. Both bodies of water are being monitored.

“Waters experiencing a toxic algae bloom will often appear murky or bright green, sometimes with a surface scum that resembles green paint,” he said.

Health departments monitor the waters and report to the Department of the Environment if they see any of the blue-green algae bloom, he said in the email.

Blooms can be caused by different types of algae. Some can cause symptoms in humans, such as skin or respiratory irritation, said Maureen Regan, a spokeswoman with the Maryland Department of Health.

Dogs have died around the country after exposure to algae blooms, as the toxins can damage their liver, kidneys and nervous system, she said.

“For the most part, there are no specific treatments for exposure,” Regan said in the email.

Pet owners are encouraged to prevent their animals from swimming or playing in waters where cyanobacteria are blooming.

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Heather Mongilio is the health and Fort Detrick reporter for the Frederick News-Post. She can be reached at

(2) comments


Loudoun County. Route 9. South of Hillsboro. On the left. Pond near the road, it’s green, and looks like a layer of green paint, just as described in the write-up


It would be nice if the FNP either provided more useful details in their articles or at least links such as: where one can find out more information.

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