Weather Forecast


MPCA warns of blue-green algae potential

ST. PAUL -- With hot weather in the forecast, the Minnesota Pollution Control Agency is warning of the potential for blue-green algae in Minnesota waters.

The algae thrive in hot weather and nutrient rich waters, and it can be toxic to both animals and humans. It can cause severe illness and in some cases death.

So far this summer, the MPCA has not received any reports of dogs, other animals, or humans being affected, according to a news release from the agency.

Most algae are harmless but can pose health risks under the right conditions.

"High rainfall, which has been common throughout much of Minnesota this spring, results in nutrient-rich runoff entering our lakes, fueling algae growth," MPCA lakes expert Steve Heiskary said in the release. "While spring and early summer temperatures were cooler than normal, lake temperatures have warmed rapidly. Given these conditions, we are likely to see blue-green algae blooms on many of our lakes."

Blue-green algae thrive particularly in warm, shallow, nutrient-rich lakes and are often blown toward downwind shorelines. Blooms that are harmful often have a bad odor and have been described as pea soup, green paint, or floating mats of scum.

"You don't have to be an expert to recognize an algae bloom that might be harmful," Heiskary said. "If it looks bad and smells bad, don't take a chance. Stay out and keep children and pets away from the water until the bloom subsides."

Animals that ingest the toxins can have a variety of symptoms, including skin irritation; vomiting; circulatory, nervous and digestive problems; and severe skin lesions. They may also suffer convulsions and die.

Humans are rarely affected, probably because the unpleasant odor and appearance of a bloom keeps them out of the water.

There are no short-term solutions to handle a bloom. Once it occurs, the only option is to wait for significant rainfall, wind shifts or cooler temperatures to disrupt the algae growth.

Over the long term, the key to solving algae problems is to reduce the amount of phosphorus that is allowed to flow into lakes through runoff.