Risks Associated with Harmful Cyanobacterial Blooms (HCBs) Continue Despite Cooler Temperatures

Wyoming Department of Environmental Quality  | view as a webpage

Wyoming Department of Environmental Quality

Risks Associated with Harmful Cyanobacterial Blooms (HCBs) Continue Despite Cooler Temperatures

Although fewer people are recreating in Wyoming’s lakes and reservoirs this fall as water and air temperatures decrease, the Wyoming Department of Health (WDH), the Wyoming Department of Environmental Quality (DEQ), and the Wyoming Livestock Board want to remind people, including hunters and fisherman, to continue to avoid and keep animals away from harmful cyanobacterial blooms (HCBs) that may be present. Although most blooms occur during the warmer summer and fall months and are expected to dissipate as temperatures decrease, some types of cyanobacteria are known to persist in freezing conditions and may continue to pose health risks to people and animals.

Recreational use advisories issued by the WDH continue to be in place for a number of waterbodies, as shown on the Wyoming HCB Advisory Webmap. Consistent with Wyoming's HCB Action Plan, the advisories will remain in place until blooms have fully dissipated and cyanotoxin concentrations are below recreational use thresholds. The DEQ will continue to monitor waterbodies this fall and winter until weather conditions deteriorate and will provide updated information on sampling results and advisory status via the webmap. When the WDH removes an advisory from a waterbody, details will also be provided on the webmap. The DEQ will send listserv notices in the event that the WDH needs to issue any new recreational use advisories.

For waterbodies with blooms, the Wyoming Department of Health and the Wyoming Livestock Board continue to recommend the following:

  • Avoid contact with water in the vicinity of the bloom, especially in areas where cyanobacteria are dense and form scum.
  • Do not ingest water from the bloom. Boiling, filtration, or other treatments will not remove toxins.
  • Rinse fish with clean water and eat only the fillet portion.
  • Avoid water spray from the bloom.
  • Do not allow pets or livestock to drink water near the bloom, eat bloom material, or lick fur after contact.
  • If people, pets, or livestock come into contact with a bloom, rinse off with clean water as soon as possible.

Questions about health effects and recreational use advisories can be directed to Courtney Tillman, Surveillance Epidemiologist, Wyoming Department of Health, at courtney.tillman@wyo.gov or (307) 777-5522. Questions regarding cyanobacteria sampling can be directed to Kelsee Hurshman, Natural Resource Analyst, Wyoming Department of Environmental Quality, at kelsee.hurshman1@wyo.gov or (307) 777-2073.

For more information on HCBs and recreational use advisories in Wyoming, visit WyoHCBs.org.