FARGO-The early start to summer caused many lakes and reservoirs to warm up and produced a rash of potentially dangerous blue-green algae blooms across North Dakota.
The blue-green algae-which can be toxic to people, pets and livestock-thrive in warm, still water, health officials said.
Because hot weather came early this spring and stayed, bodies of water have had more time to warm, creating ideal conditions for algae, said Mike Ell, an environmental scientist with the North Dakota Department of Health.
Calm weather, with lots of sunlight, also promotes algae growth. "That's what really stimulates these blooms," he said.
So far, health officials have posted warnings or advisories at a handful of lakes or reservoirs around the state. It's been a more active summer than usual for blue-green algae blooms, Ell said, and the risk likely will continue through August.
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North Dakota health officials and the state veterinarian have received no reports thus far of illnesses in people, pets or livestock from blue-green algae blooms. Similarly, Minnesota health officials have not received reports of any illnesses.
"Given the conditions we've had so far, we encourage people to check their water," said Susan Keller, North Dakota's state veterinarian. Except in areas that have received heavy rains, livestock producers can check with local veterinarians to see if there have been problems from algae in stock ponds.
Earlier this month, Patterson Lake, a recreational lake near Dickinson, was found to have levels of the microcystin toxin two to nine times the recommended safe levels, according to testing by the state.
Levels of the blue-green algae toxin have subsided then, but an advisory remains in effect for the lake. No swimming is advised and boaters are urged to use caution, avoiding accidental ingestion of the water.
Earlier this week, health officials issued a blue advisory for two bodies of water in LaMoure County - Lake LaMoure and Twin Lakes - both popular recreational spots. The levels weren't enough for a warning, but health officials wanted to alert the public to be vigilant, especially with hot weather in the forecast.
In June, health officials warned the public about the risks of exposure to blue-green algae at Homme Dam near Park River.
In recent years, North Dakota officials have been more active in sending out warnings and advisories about blue-green algae blooms and, as a result, more reports are coming in from the public, Ell said.
People or animals that swallow water containing the cyanotoxins in the algae can become sick. Symptoms include severe diarrhea and vomiting; numb lips, tingling fingers or toes; dizziness, rashes, hives or skin blisters.
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If people or pets are exposed, they should be rinsed off with fresh water as soon as possible, health officials advise.