Toxic bacteria found in Zion National Park, NPS says

Cyanobacteria attached to the side of the river in Zion. Note the yellow/brown color and vein...
Cyanobacteria attached to the side of the river in Zion. Note the yellow/brown color and vein like texture(National Park Service)
Published: Jul. 31, 2023 at 7:13 PM PDT
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LAS VEGAS, Nev. (FOX5) - The National Park Service (NPS) has issued health watches and warnings for a river and two creeks in Zion National Park due to toxic cyanobacteria and cyanotoxins.

According to NPS, a health watch is in effect for the North Fork of the Virgin River and the La Verkin Creek, which is a tributary of the Virgin River. A warning, which NPS notes is more serious, is in effect at North Creek, also a tributary of Virgin River.

Visitors are advised not to drink stream water anywhere in the park.

An NPS web page explains that Cyanobacteria, also known as “blue-green algae,” are photosynthetic bacteria found in lakes, reservoirs, rivers, streams, and other bodies of water in many places throughout the world. In Zion, scientists have found cyanobacteria at the bottom of the Virgin River and its tributaries within the park.

The kind of cyanobacteria attached to the bottom of the river is known as benthic cyanobacteria, and it grows on rocks, plants, at the sides of the river and along the river’s edge. NPS added that Cyanobacteria are naturally occurring but can harm humans or animals because some produce cyanotoxins.

According to the US Environmental Protection Agency, when people are exposed to cyanotoxins, they can experience a range of symptoms. These can include a mild skin rash, serious illness, or in rare circumstances, death. Severe illnesses caused by short-term exposure to cyanobacteria and cyanotoxins during recreational activities like swimming include hay fever-like symptoms such as skin rashes, respiratory, and neurological or gastrointestinal distress.

Drinking water contaminated with cyanotoxins could cause liver and kidney damage. If you are exposed to cyanobacteria, seek immediate medical attention and contact the Utah Poison Control Center at (800) 222-1222. If you are experiencing a medical emergency, call 911.

More information, including tips for identifying cyanobacteria, is available here.