With hot summer weather, the North Dakota Department of Environmental Quality is alerting people to be on the lookout for blue-green algae (cyanobacteria) in the state’s water bodies. Blue-green algae discolors water and can cause foam, scum or algal mats to appear on the surface. The water also may have the appearance of spilled green paint or pea soup.

Blue-green algae can produce toxins called cyanotoxins, which can make people and animals sick if swallowed. Symptoms may include diarrhea and vomiting; numb lips, tingling fingers and toes; dizziness; or rashes, hives or skin blisters. In severe cases, cyanotoxins can cause death and there are no known antidotes. Children are at higher risk because of their smaller size.

“Algae blooms are most common in North Dakota in late summer; however, it only takes a few hot days to cause a bloom,” said Aaron Larsen, NDDEQ Division of Water Quality. The NDDEQ tests water for cyanotoxins and, if detected, issues advisories to the public. However, it can take time to receive test results, so people are advised to avoid water that is discolored, scummy or smells bad.

“A primary concern with cattle affected by cyanobacteria is that harmful algal blooms can occur quickly, within a day," said Dr. Michelle Mostrom with NDSU’s Veterinary Diagnostic Laboratory. "It’s difficult for livestock producers to check water quality daily or every other day — very important in cases of cyanotoxin poisoning. Some cyanotoxins are quick-acting neurotoxins and can kill livestock in a few minutes to a few hours; no treatment will be effective after the toxin has been absorbed."

The NDDEQ and North Dakota Department of Agriculture recommend the following:

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• Respect blue-green algae advisories announced by public health authorities.

• Do not swim, water ski or boat where water is discolored or where you see foam, scum or mats of green or blue-green algae.

• If you accidentally swim in water that might have a blue-green bloom, rinse off with fresh water as soon as possible.

• Do not let pets or livestock swim in or drink from areas where water is discolored or where you see foam, scum, or mats of algae.

• If pets (especially dogs) swim in scummy water, rinse them off immediately — do not let them lick off the algae (and toxins).

• Do not irrigate lawns or golf courses with pond water that looks scummy or smells bad.

To learn more about the effects of blue-green algae blooms on pets and livestock, contact the North Dakota Department of Agriculture, Animal Health Division, at 701-328-2655.

For information on public health issues or to report a possible blue-green algae bloom, visit the NDDEQ harmful algal blooms website at https://deq.nd.gov/WQ/3_Watershed_Mgmt/8_HABS/Habs.aspx or contact the North Dakota Department of Environmental Quality, Division of Water Quality, at 701-328-5210.