Ammonium lignin sulfonate lies in a puddle after it washed off the road in Nine Mile Canyon near Rasmussen Cave after a rainstorm in May of this year.
Paul Birdsey, regional aquatics program manager for the state of Utah, determined that a dust suppressant being used by Carbon County on a section of Nine Mile Canyon Road and leaking into nearby streams, as reported by a local resident, was deemed to not be dangerous to wildlife or Nine Mile Creek in a recent letter to Carbon County officials.
In August, Carbonville resident Steve Tanner observed and photographed suppressant material from the road being washed into a stream. He reported the problem to the U.S. Fish and Wildlife Service, who, in turn, contacted the state of Utah about the problem.
After having a conversation with Tanner about the situation, Birdsey contacted Carbon County and obtained a material safety data sheet relating to the compound being used on the road. He learned that the material was ammonium lignin sulfonate, which was supplied to the county by a company from Greeley, Colo. The applications process was being completed by Nielsen Construction, under a contract with the county and the Bill Barrett Corporation.
Ammonium lignin sulfonate ("ligs" as they are called) is a byproduct of paper manufacturing, and is included in a class of dust suppressants described as organic and non-petroleum based. After a search of literature, the Department of Natural Resources found that ligs are water soluble and can be washed into streams during a rain storm. So, based on the photographs, the ligs were being washed into the stream, but the department also found that the direct effects of the material are low enough that the material has been classified as non-toxic by the U.S. Food and Drug Administration.
As the material becomes water soluble and breaks up, it changes the water where it is applied to a dark brown color that is nearly black. This transformation was observed in the stream in the canyon.
"While unsightly, a review of the available literature suggests that the environmental hazard from runoff of lignosulfonate into Nine Mile CreekÂ appears to be minimal," wrote Birdsey in a letter to the county. "The solubility of the material which can cause it to move from the road surface during storm eventsÂ would also result in it being quickly diluted in and receiving water."
Birdsey said that the conclusion is based only on runoff and not on a case where the material would be directly applied to a stream.
As for possible fish kill or damage, Birdsey also noted that the "relatively sparse population of fish in Nine Mile Creek further reduces the concern for runoff into the system."
He noted that the greatest environmental hazard to aquatic life in the stream at present is probably the dust and the sediment from the untreated section of the road and not the almost 19 miles of roadway that has been treated.
However, Birdsey also made some recommendations to the county to take care in using the material. The letter said that the county should be sure the material is being applied according to the manufacturer's specifications. He added that it should not be directly applied in its undiluted form to any stream and that a berm should be constructed along sections of the road where the stream runs alongside it. Other recommendations stated that the contractor utilizing the material should use a vacuum truck to vacuum up standing puddles of the lig after a rain storm, and that a French drain or other method of runoff control should be built in the area of road crossings through streams to prevent the material from entering the stream.