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Hazardous algal blooms identified in 2 Montana waterways

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Posted at 8:08 AM, Jul 14, 2022
and last updated 2022-07-14 10:08:43-04

HELENA - The Montana Department of Environmental Quality (DEQ) has issued two caution advisories for harmful algal blooms (HABs) in the state.

One of the warnings is for the Duck Creek Campground along Canyon Ferry Lake which has been confirmed to have harmful toxins.

"They are an overgrowth of a certain type of algae, actually cyanobacteria that when it grows and proliferates has the potential to produce a toxin that can sicken humans and even kill animals and livestock," said DEQ Water Quality Specialist Hannah Riedl.

DEQ is asking the public to report any suspicious lining on water. The algal blooms can have an appearance similar to "pea soup," "grass clippings," or "spilled paint," and even have colors like red, green, or blue.

Helena reservoirs like Lake Helena and Canyon Ferry have a history of producing harmful algae

"When we have a lot of hot still days without a lot of wind, and then there's a lot of sunshine. So the storms we've had this spring have helped mix things up and kind of disturb the Habs from forming," said Riedl.

Summer had a late start this year, which can make a long season for the potential for toxic algae to form.

"We start getting reports of HAB's as early as late May or early June and then we keep getting reports typically throughout October," said Riedl.

Symptoms can start within a few hours of exposure and last two to three days. In humans and animals, symptoms may include:

  • Skin, ear, eye, nose, or throat irritation. 
  • Respiratory issues. 
  • Lethargy, paralysis, tremors or seizures. 
  • Abdominal pain, diarrhea, or vomiting. 

People who suspect an area may have toxic algae should not swim or boat in the area and keep pets and livestock away from the water. as the algae can be fatal if ingested.

"The dose makes the poison, so it depends on how much you're exposed to and for how long, and then that may correlate to just how sick you or your animal might become if they become into contact with the harmful algal blooms," said Montana Department of Health and Human Services Epidemiologist Laura Williamson.

If you notice something strange in the water and believe it to be a harmful algal bloom, you can report it here.