Erosion Control May 2012 : Page 44
Sustainable dust control is quickly becoming a reality. BY DAVID C. RICHARDSON Science on the Horizon W hen it comes to dust, the effects from the hand of nature may appear a bit more dramatic than those generated by the activities of humans. The catastrophic eruption of Mount Krakatoa in 1883 blasted an immeasur-able quantity dust 4 miles into the atmo-sphere, where it persisted for up to four years, blocking sunlight and drifting to span the globe, lowering temperatures by a full degree. The great dust storm of November 12–13, 1933, started in the plains of the United States and caused discoloration of snow a half continent away in New England, where, according to reports of the time, it deposited 25 tons of dust per square mile. However, dust tossed up from roads, industrial sites, farms, and practically any other site per-turbed by humans does have its impact; it can travel vast distances over extended periods of time. And it can get into, and practically ruin, pretty much anything. Bethany Williams, a biologist for the US Geological Service, explains that dust can act as a vehicle to carry con-taminants like metals into roadside streams, and the dust itself can contrib-ute to sediment loads in aquatic habitats. “There are obvious health concerns with PM 10 and PM 2.5 dust [smaller than 10 and 2.5 micrometers, respectively], and road dust makes a substantial con-tribution to both of those categories. Several studies show it can cause crop in-jury and inhibit photosynthesis if plant leaves are coated with dust, and at least one study indicated that dust on forage crops can cause excessive tooth wear for livestock,” Williams says. “There are very good reasons to keep dust out of the roadside habitat as much as possible.” And the animals in their own way may let on precisely how they feel about dust in their environment. Alan Sarver says ranchers in the Dakotas have com-plained that their sheep and other live-stock turn up their snouts to grazing anywhere near dusty gravel roadsides. Dust Rush Sarver, who operates Z&S Dust Control, providing dust control services along rural roads in places like McKenzie County, ND, has seen his business boom in the past few years—not because of the sensitive palates of sheep and cattle, but because of the voracious appetite the rest of us have for oil. The oil fields in North Dakota are booming, thanks to the Bakken Formation, a petroleum-rich geologi-cal feature stretching over parts of the Dakotas and Montana. Advances in hydrofracking and horizontal drill-ing techniques, and an oil market that makes the investment worthwhile, has some experts comparing events in the Dakotas today to the early days of the historic Texas oil rush. What it means to Sarver is tons more dust-churning traffic on McKenzie County’s gravel roads. “Just a few years ago,” he says, “you would have seen maybe 30 to 40 or 50 farm-to-market trucks per day, but now it’s more than 1,000 vehicles, run-ning 24 hours a day—and all of them semis.” Sarver says not even an asphalt paved road could hold up long to that kind of onslaught. To illustrate the severity of the dust problem, Sarver says, the governor of North Dakota recently offered to take reporters up in helicopters “just to show them. From the distance you can see dust in the air. There is just so much traffic, and even after all the roads that they‘re shooting, it’s not enough; you can literally see it. When you get within 50 miles you can see it on the horizon.” 44 EROSION CONTROL WWW.EROSIONCONTROL.COM
Science on the Horizon
David C. Richardson
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