Contact: Jennifer Groebner, 651-296-7706
St. Paul, Minn. - Recent hot, dry weather has created conditions where toxic blue-green algae can form on Minnesota lakes. The algae is thought to be responsible for the death of a dog in Wright County last week, according to the Minnesota Pollution Control Agency (MPCA).
Blue-green are a form of aquatic algae that normally exist in many Minnesota waters, but in the right conditions, can become toxic. The MPCA has reminded people the past several years that this type of algae can harm pets, livestock and even people.
"Normally this becomes a concern later in the season. But the fact we're seeing toxic blue-green algae in early summer is not that unusual, and shows how unpredictable it can be," said MPCA lakes expert Steve Heiskary. He is part of an interagency work group that's spreading the word that blue-green algae should be avoided. "When in doubt, best keep out," says a poster the group has distributed around the state.
Algae are microscopic aquatic plants, and are a natural part of any aquatic ecosystem. There are hundreds of species. Under the right conditions, algae populations can "bloom" with dramatic growth, turning the water cloudy and green, a sight familiar to most summertime lake-goers.
Most algae blooms are harmless. But blue-green algae, when present in the water in high concentrations, can produce potent toxins that can affect humans or animals. Blue-green algae are found throughout Minnesota, but thrive particularly in warm, shallow, nutrient-rich lakes.
As algae concentration can vary widely across the lake, so can associated toxins. Often occurring on downwind shorelines, high algal concentrations may produce harmful conditions. It is these near-shore blooms where humans and animals most often come in contact with the blue-green algae and where the risk of algal toxins is greatest. Harmful effects on humans are not often reported, probably because the unpleasant appearance and odors of a blue-green bloom tend to keep people out of the water. But human health effects can include irritation of skin, eyes and nasal passages, and nausea and vomiting. Extreme cases can produce paralysis and respiratory failure.
Distinguishing blue-green algae from other types may be difficult for non-experts. But toxic blooms generally look pretty nasty, sometimes said to look like pea soup, spilled green paint or floating mats of scum. They often smell bad as well. While such conditions would seem to keep most people away, it's surprising how many still will swim or wade in such waters or let their animals enter it.
"You don't have to be an expert to recognize water that might have a toxic algae bloom," Heiskary said. "If it looks bad and smells bad, it's probably best not to take chances with it."
For more information about toxic algae blooms, go to www.pca.state.mn.us/water/clmp-toxicalgae.html, or call 651-296-6300 or 1-800-657-3864.