In an effort to reduce the environmental impact of the magnesium chloride included in many dust-control chemical products, San Miguel County, Colorado, road crews are testing a new synthetic chemical from Greeley-based EnviroTech Services on a one-mile stretch of unpaved road in Ophir.
The test chemical, which was applied in early May, will be studied by both the county and EnviroTech Services in order to determine if it might be appropriate for the rest of the county’s roads. The county’s road crews use chemicals each spring to reduce dust on 45 miles of unpaved county roads.
“We’re always looking for something better for the environment that will work on the roads, stabilize and keep the dust down,” county Road Superintendent Mike Horner said. “We’ll keep trying any new products that come along.”
A 2009 Colorado State University study found that magnesium chloride concentration levels caused by dust repression chemicals similar to the ones used by San Miguel County probably don’t seriously impact water quality in roadside streams, but also indicated that plants near chemically treated roads were impacted.
“Although MgCl2 [magnesium chloride]-based dust suppressants did move into some roadside streams, the concentrations detected were below those reported to adversely affect fresh water aquatic organisms, but the ultimate fate of these ions in Colorado water bodies are not known,” the study, primarily funded by Larimer and Grand counties, found.
The study recommends non-chloride based products for dust suppression or application-rate reductions.
According to information provided to the county by EnviroTech Services, the new dust suppression chemical does reduce magnesium chloride application rates.
The blend currently used by the county results in 1.138 pounds of magnesium chloride per square yard, while the new chemical leaves 1.026 pounds.
Though the reduction is important, Horner said the county still needs to determine if EnviroTech’s dust suppression chemical is cost and time-effective. The technique to apply the new chemical is more intensive, requiring the roads to be regraded multiple times and the chemical to be applied at three different depths.
“This product is more expensive and more labor intensive. Unless it really works, we probably don’t have a lot of time to spend doing the miles,” Horner said.
“We’re monitoring its effectiveness, along with a chemist from EnviroTech, and we’ll know by the end of summer if it’s worth the extra money and time to put it in.”
“We’re hoping this will stabilize the road and hold dust for most of the summer,” Horner added. “It’s a little more costly but has a lot less chloride in it.”