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Harmful algal bloom found in Virgin River believed to have killed dog

SHARE Harmful algal bloom found in Virgin River believed to have killed dog

The Virgin River at Zion National Park is pictured.

Matt Gade, Deseret News

ZION NATIONAL PARK — State environmental leaders have identified a harmful algal bloom that may have killed a dog after it went swimming in Zion National Park’s Virgin River.

The Utah Department of Environmental Quality made the announcement Friday night, saying they received a report from Zion National Park on July 4 that a dog died an hour after swimming in the North Fork of the Virgin River. 

“The dog was playing in the river and at one point was ‘snapping’ at algae growing on the rocks,” the press release said. “Prior to its death, the dog exhibited symptoms consistent with possible exposure to cyanobacteria toxins — those produced by harmful algal blooms. The dog could not walk, was in pain and was having seizures.”

Water samples taken from the river show anatoxin-a concentration exceeding 55 micrograms per liter. According to the press release, the health threshold for recreation is 15 micrograms per liter — far below the current levels.

Harmful cyanobacteria were also identified in additional areas of the Virgin River’s North Fork.

A public health warning has been issued for the affected area and signs will be posted to inform visitors about the risks of exposure. Zion National Park also posted signs that warn guests not to swim and to keep pets out of the water.

State leaders are working with the impacted local communities to work to make sure drinking water that originates from the river is safe. Washington County Water Conservancy District, Zion National Park and the dual towns of Virgin and Rockville are currently not using the North Fork of the Virgin River as a drinking water source, according to the press release.

Zion National Park, local authorities and the Department of Water Quality plan to collect further samples this upcoming week that will gain better insight into the extent of the concern.

Those who may have been exposed are advised to call their physician or Utah Poison Control at 800-222-1222. Sampling updates are posted to habs.utah.gov.