Pet warning in Maryland: Toxic algae found in Potomac River and Wye Mills Lake

The Maryland Department of the Environment has issued a health alert, warning residents to keep their pets out of the Potomac River due to the presence of harmful algae mats. 

These mats have been detected in two locations: near Cumberland and in the area stretching from below Williamsport to Riley's Lock.

According to MDE, these algae mats can be dangerous if ingested by animals. The algae, known as cyanobacteria or blue-green algae, are microscopic organisms that can rapidly grow out of control in fresh water, forming harmful algal blooms. 

In a related advisory, the Maryland Department of Natural Resources has posted a Harmful Algal Bloom Advisory at Wye Mills Lake in Queen Anne's County. 

A cyanobacteria bloom in the lake has produced algal toxins that exceed the recommended level for safe recreational contact. Boaters and anglers are urged to exercise caution in this area and, if possible, choose other locations. 

The DNR advises that anyone at Wye Mills Lake should avoid swimming in or drinking the water, avoid contact with any green water and scum, and keep children and pets away from the lake.

What are harmful algal blooms?

The Centers for Disease Control and Prevention explains that some of these blooms produce toxins that can make both people and animals sick. For pets, swallowing water contaminated with cyanobacterial toxins can lead to severe illness or even death within hours or days.

Harmful algal blooms can appear as scum, spilled paint, foam, or mats of algae on the water’s surface, and they can change the water’s color to blue, green, brown, yellow, orange, or red.

Pet owners are advised to keep their animals away from the affected areas until further notice. The MDE plans to continue to monitor the situation and will provide updates as necessary. 

If you're concerned about cyanobacterial toxin poisoning in your pet, contact a local poison control center.