Toxic ‘blue-green’ algae found in Lac qui Parle Lake

Blue-green algae, which can be toxic to humans and pets, appears to be in bloom in backwaters of Lac qui Parle Lake west of Milan. The bloom was noticed this past weekend by Minnesota Pollution Control Agency staff travelling along Minnesota Highway 40.
The MPCA advises pet owners to check water conditions when dogs are playing near lakes or slow-flowing streams. Blue-green algae “blooms” have a thick, cloudy appearance that can look like green paint, pea soup or floating mats of scum.
Some, but not all, species of blue-green algae contain potent toxins that can be deadly to dogs, livestock and other animals within hours of contact.

If possible, dog owners should keep their pets away from algae-laden water entirely.
If animals do enter water with heavy algae growth, they should be hosed off right away, before they have a chance to lick themselves clean. Animals become ill when they ingest the toxins, so preventing them from drinking affected water or licking toxins from their coat is key to preventing illness.


If someone is concerned that their pet has been exposed to harmful blue-green algae, they should take the animal to a veterinarian immediately.


Blue-green algae blooms can occur anytime during the summer, though they are normally associated with warm weather and low rainfall. Algae are a natural part of the ecosystem, but under certain conditions, algae populations can “bloom” with dramatic growth. Most blue-green algae are not toxic, but there is no way to visually identify whether a particular bloom contains toxins that are harmful to people or animals.


The best way to prevent algal blooms over the long term is to reduce the amount of nutrients that run off into lakes from fertilizers and organic materials such as leaves and yard waste. Once a bloom has developed, there is no way to correct it.
Photo:  This example of blue-green algae was found in Blue Earth County.