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Toxic Cyanobacteria Confirmed In Several Zion National Park Waterways

Zion National Park visitors beware! The National Parks Service has confirmed that several waterways within Zion contain toxic cyanobacteria and cyanotoxins.

The Utah Department of Environmental Quality sets three advisory levels for still and flowing water within Zion: health watch, warning, and danger. Health watch is the lowest in the scale, but means that a harmful algae bloom (which includes cyanobacteria) has been confirmed in the body of water. Two bodies of water within the park, North Fork of the Virgin River and La Verkin Creek, are currently on health watch. North Creek, a tributary of Virgin River, is marked as “warning”, a step above health watch.

Swimming in these bodies of water is still acceptable (unless anything is changed to “danger”), though visitors should refrain from submerging their heads. Most importantly, do not drink water from any streams within the park. Filter water directly from springs only, and don’t think that boiling will do the trick. There are currently no known recreational ways to remove cyanobacteria and cyanotoxins from water.


Cyanobacteria, or “blue green algae”, can be found in bodies of water throughout the entire world. Benthic cyanobacteria, which scientists have found in Zion, grows on rocks, plants, the side of rivers, and on the river’s edge. Though they are naturally occurring, cyanobacteria produce cyanotoxins, four of which (anatoxin-a, microcystin, nodularin and cylindrospermopsin) have been discovered in the park.

The range of symptoms one may experience if exposed to cyanobacteria is pretty large, with everything from irritation on the skin, eyes, ears, nose or throat to seizures and incoherent speech on the table. Pets are also susceptible to contamination, with the potential for paralysis, tremors, vomiting, and more.

If you think you’ve been exposed to cyanobacteria in Zion and have any symptoms, seek medical attention immediately and contact the Utah Poison Control Center by calling (800) 222-1222.

Related: U.S. National Parks Are Free This Friday!

Image Credit: Zion National Park via Facebook