Virgin River

Learn

In July of 2020, the Utah Department of Environmental Quality’s (DEQ) Division of Water Quality (DWQ) and the National Park Service (NPS) detected toxic cyanobacteria algal blooms in multiple areas of the North Fork of the Virgin River. Cyanobacteria are a natural part of aquatic environments, but can be harmful to water quality and aquatic life if they produce toxins. The colonies of cyanobacteria found in the Virgin River produce the cyanotoxin called anatoxin-a, which can be harmful to humans and dogs. Exposure can occur through ingestion, inhalation, skin contact, and eye contact with toxin-contaminated water.  

Zion National Park continues to monitor monthly for the presence of harmful cyanobacteria and cyanotoxin's. Learn more about the current warning and health watch advisories in effect. 

Look

Colonies of cyanobacteria in the North Fork of the Virgin River, North Creek, and La Verkin Creek can be yellow, tan, green, brown, or black in color. These colonies can be hard to see because some blooms grow on or near the bottom of water bodies in the benthic zone. You cannot tell if a water body has a harmful bloom by looking at it.

If a current warning or health watch advisory is in effect:

• Do not swim or put your head under the water anywhere in Zion National Park. Children are especially vulnerable to cyanotoxins, so be mindful of where they go if you are near a body of water like the Virgin River. 

• Keep dogs on a leash in and out of the water. Dogs are vulnerable to cyanotoxin exposure because they may bite or accidentally eat/drink material from potentially toxic algal mats. 

• Do not drink any water from streams or rivers in Zion National Park. There is no known recreational water filtration method that is effective at removing cyanotoxins. 

• Contact the Utah Poison Control Center at (800) 222-1222 with concerns about cyanotoxin poisoning and call 911 in the event of a medical emergency. Symptoms can include, but are not limited to, skin rash, salivation, drowsiness, tingling, burning, numbness, pain, incoherent speech, seizures, vomiting, and diarrhea. 

Connect

Algae, cyanobacteria, and their toxins can harm ecosystems including people, animals, and local environments. There are many factors that influence the growth of harmful algae and cyanobacteria in water, such as nutrient levels, temperature, low flow during a drought, and conditions like pH or turbidity, as well as the rise of deep ocean water. Are any of these factors influenced by humans?