Toxic blooms can sicken humans and kill pets and livestock
Summer is in full bloom. Before you take a dip in the lake this summer, state agencies are urging Montanans to know the health risks of Harmful Algal Blooms (HABs).
Clearwater Resource Council received reports of possible blue-green algae in Seeley Lake. Water samples have been sent it to test for toxicity. The HAB website listed a report dated Aug. 6 that read, “No visible bloom, but a dog presented with acute neurologic signs and death in less than an hour after swimming in the river that leads into Seeley Lake. Last week a different dog suddenly drowned in the area as well.”
No advisories have been issued for the area but CRC Executive Director Caryn Miske said, “Until we have confirmation on the samples, it is probably best to ask people to be aware and report any possible sightings to CRC ASAP.”
Miske can be reached by calling 406-677-0069 or email caryn@crcmt.org
HABs are caused by blue-green algae that are native to Montana’s freshwater lakes and reservoirs. Scientists believe the blooms are occurring at more locations, with increased frequency and longer duration. Causes include warmer water temperatures, longer summer growing seasons and increased nitrogen and phosphorus runoff from a variety of human activities. Under certain conditions, HABs can produce toxins that damage the skin, liver and nerve cells. They can make people sick and kill pets and livestock.
Not all varieties of blue-green algae are harmful, but some can produce dangerous cyanotoxins. Blue-green algae blooms often look like pea soup, grass clippings or green latex paint. The algae are usually suspended in the water or aggregated into floating mats. Blue-green algae are single-celled organisms, so they will not appear thread-like or stringy like roots, mosses, water plants or green algae.
Since 2017, Montana’s HAB program partners - the Department of Environmental Quality and the Department of Public Health & Human Services - have enlisted the public’s help to track suspected HABs.
“The goal of the Montana HAB Program is to educate people about the potential dangers of HABs, how to identify them and how to respond,” said Hannah Riedl, water quality specialist at DEQ. “Because we can’t be there to track rapidly changing conditions in every water body, we want people to be informed enough to make their own decisions. We also ask the public to be our eyes on the ground and report HABs. That way, we can respond quickly and hopefully prevent people, pets, and livestock from getting sick.”
Where have HABs been present in the past? Between June and October of 2019, the Montana HAB Program received 48 reports of HABs on Montana’s lakes, reservoirs and ponds. Last year, two temporary closures were issued due to HABs. The Cow Creek Reservoir (Blaine County) temporarily closed due to microcystin levels of 50 mg/L, well above the recreational guidelines of 8 mg/L. Additionally, White Sandy Beach on Hauser Lake (Lewis and Clark County) temporarily closed due to microcystin levels detected with test strips. Other lakes and reservoirs that were visually confirmed in 2019 to have cyanobacteria present were Cooney Reservoir (Carbon County), Wadsworth Pond (Cascade County), Hebgen and Hyalite Reservoirs (Gallatin County), Bearpaw Lake and Beaver Creek Reservoir (Hill County), Canyon Ferry and Holter Reservoirs (Lewis and Clark County), Seeley Lake (Missoula County), Noxon Reservoir (Sanders County), Medicine Lake (Sheridan County) and Lake Elmo (Yellowstone County).
What are the health impacts of HABs? Certain species of cyanobacteria can produce cyanotoxins that can pose serious health risks to human, pets, and wildlife. Exposure to cyanotoxins may occur through contact with or ingestion of contaminated water.
HABs are receiving increased attention nationally because of the potential human health and economic impacts. Reports of livestock and pet illness and death have been reported since the 1970s, including as recently as this year.
“During a pandemic it’s especially important to take precautions to protect the health of yourself and your loved ones,” said Ed Evanson, supervisor of the DPHHS Food and Consumer Safety Section. “When in doubt, stay out. Keep a close eye on pets and livestock to ensure they don’t drink the water where HABs are present.”
Do not drink, swallow, or swim in water that shows signs of a HAB, and be sure to keep kids and pets or livestock out. Direct contact, ingestion or inhalation of cyanotoxins may irritate the skin, eyes, nose, throat and respiratory system, or cause nausea, vomiting, diarrhea, headache or liver and kidney damage.
If you suspect a HAB-related illness in a person or animal, including livestock, call Poison Control immediately at 1-800-222-1222.
Learn how to report a suspected HAB at www.hab.mt.gov or call 1-888-849-2938. You may also report a suspected HAB by email to HAB@mt.gov
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