High levels of nitrate seen where fish died

High levels of nitrate were found in Parleys Creek, where hundreds of cutthroat trout died last week.

"I hope I can say that is the culprit," said Mike Slater, an aquatic biologist at the Utah Division of Wildlife Resources. "How and where and what produced those high levels, I do not know."

The nitrate level in the creek at Parleys Nature Park was 1.66 milligrams per liter on June 26, double the highest level in the past, according to a sample collected by the city.

"It was very unusual to get readings that high," said Florence Reynolds, a water-quality manager.

More than 400 dead trout were discovered that same day. The source of nitrate was not known.

"You can get nitrates from fertilizers. That's the first thing that pops into my mind," Reynolds said. "I don't know what other kinds of material would have a heavy enough nitrate level to show up like that."