Results of a water test released this week have lent little, if anything, to an investigation by the Idaho Department of Environmental Quality of a fish kill in Elkhorn Creek on May 31.
The test, conducted at University of Idaho's Food Quality Assurance Lab on the campus of the College of Southern Idaho, sought traces of diquat dibromide, an herbicide that is slightly toxic to fish.
"At the time we pulled the sample there was no diquat present," said Sonny Buhidar, DEQ water quality regional manager.
However, Buhidar said that does not rule out that diquat dibromide was the cause of the fish kill.
"It just means that when the sample was pulled there was none," he said.
DEQ took its water sample mid-morning on Friday, June 1. Investigators have not determined exactly when the contamination occurred, but believe it was sometime the previous evening.
"Diquat has a half-life of about 48 hours," Buhidar said, but added that that is in standing water. He said it can dissipate much quicker in moving water.
DEQ is also testing water samples for Cutrine-Plus, an algaecide registered by the Environmental Protection Agency for use in drinking-water reservoirs, in lakes that farm fish and in golf course water hazards. As with all algaecides and herbicides, the key factor is concentration levels. That test is still underway at a lab at the University of Idaho in Moscow and is expected to be available in one to two weeks.
The tests are part of a larger, multi-agency investigation.
The Idaho State Department of Agriculture is testing water and fish tissue samples. Communication Director Pamela Juker said some of the department's water tests are complete but it is waiting for all results to come in before releasing its findings.
Idaho Fish and Game announced plans to seek restitution for the nearly 150 wild rainbow and brook trout that died in the incident and for its time investment, said Dave Parrish, Magic Valley regional supervisor. Parrish estimates the cost to be $450, but has not named the responsible party. More fines and sanctions could be levied by other agencies.
Parrish said investigators are "fairly certain" the contaminant came from the Elkhorn Golf Course.
"We know there was a contractor working on treating aquatic vegetation," he said.
Junker said potential fines levied by the Department of Agriculture would be "label violations for the misuse of a product." The maximum monetary penalty is $3,000. In addition, the contractor's license to work with herbicides and algaecides could be revoked. Junker emphasized that any sanctions are contingent on the results of the investigations.