This is an archived article that was published on sltrib.com in 2016, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

With elevated levels of toxins now appearing in Scofield Reservoir and 30 miles downstream in the Price River, officials are advising farmers to avoid using these waters for irrigation and ranchers to not let their livestock drink it. And the Price River Water Improvement District, which taps the Price for its drinking water, is using special equipment to disinfect drinking water.

A 3-week-old algal bloom last weekend intensified to the point this week that Scofield was closed for public recreation after high cell counts were discovered in the 2,800-acre lake at the Price River's headwaters.

Scofield is among several bodies of water in Utah that are so laden with nutrient pollution that they have become explosive breeding grounds for cyanobacteria during periods of low water and hot weather. These blooms deoxygenate the water and contaminate it with a variety of toxins that are known to sicken humans and kill animals. Last week waterfowl and bats were found dead among the thousands of rotting chubs littering the north and east shores of Scofield.

The Southeast Utah Health Department also urges people to not recreate in the Price River and has closed fishing ponds and a canal.

Cursory testing has revealed unacceptably high concentrations of the cyanotoxin known as microcystin in both the lake and river, prompting the latest rounds of advisories, according to Ben Holcomb of the Utah Division of Water Quality (DWQ). These field tests are cursory, capable of saying only whether the water exceeds a 10-parts-per-billion threshold.

On Wednesday, test strips came back positive at sample sites on the Price River near Helper, downstream from where both Price City and the Price River district maintain intakes for their water-treatment plants.

Price City has shut down its intake because it lacks the ability to decontaminate the water during algal blooms, according to the Utah Division of Drinking Water. The Price River Water Improvement District recently upgraded its ozone equipment because of the growing prevalence of these blooms and has activated it to thoroughly disinfect the water it is delivering to its customers.

"We are removing any of those toxins as well as any of the algae that can produce toxins," said the district's manager, Jeff Richens. "We are keeping a close eye on this to make sure it doesn't get worse, and if it does get worse, we will react."

Officials stressed that drinking water is safe, but pet owners should keep their dogs out of the water and be on the lookout for symptoms of poisoning.

DWQ took more water samples Friday. Samples were sent to a Florida lab and results will not be available until Monday or Tuesday.

Twitter: @brianmaffly