EPA’s long-used method of dealing with asbestos-contaminated sites — burying it in sludge to prevent the cancerous fibers from becoming airborne — could carry serious repercussions, according to a Stanford University researcher.
“People have this idea that asbestos is all covered up and taken care of,” explained Jane Willenbring, an associate professor of geological sciences at Stanford University’s School of Earth, Energy & Environmental Sciences, in an April 23 university feature release. “But this is still a lingering legacy pollutant and might be dribbling out pollution, little by little.”
Willenbring was part of a team of U.S. researchers who studied EPA’s methods for cleaning-up asbestos contamination sites and found that burying asbestos in manure and other organic components doesn’t always lock the asbestos particles down — as previously thought — but may actually speed their way through the soil and into our water supplies.
The team detailed their findings in a research paper published Jan. 27 in the Journal of Hazardous Materials Letters. Now, Willenbring is going public with the dangers.
“It’s surprising that even though these little [asbestos] fibers are so long, because their shortest diameter is small enough, they can wind their way through these soil pores.” — Jane Willenbring of Stanford
“We can show that exactly the thing that they do, which is add manure or other organic sludges to the asbestos piles that creates the production of dissolved organic matter, is exactly what causes the liberation of asbestos,” Willenbring said. “It’s actually facilitating the transport of asbestos fibers.”
Willenbring explained that the EPA’s assumptions about trapping asbestos are based in part on the shape of the mineral’s hair-like fibers, but also on a 1977 agency report that “minimized the threat of asbestos moving through soil,” according to the release. But recent research — including the January paper —is now challenging that assumption.
From Bad to Worse
Willenbring and colleagues from the University of California, the Chicago College of Osteopathic Medicine and the University of Pennsylvania determined that the addition of organic sludge “changes the electric charge of asbestos particles and makes them less sticky, thereby enabling them to move faster through soil.”
“It’s surprising that even though these little fibers are so long, because their shortest diameter is small enough, they can wind their way through these soil pores,” said Willenbring.
This could lead to asbestos exposure through unexpected means, such as inhaling fibers coming through the shower nozzle, or from a humidifier, the release states.
The team’s work was based in part on soil samples taken from an EPA Superfund site in Pennsylvania — the BoRit location — that was contaminated with asbestos. The samples were taken before the site was capped in 2008, according to the release.
The daunting scale of the problem surprised Willenbring, the release noted. She explained that there are at least 16 Superfund sites that contain asbestos, and millions of people in the U.S. live near thousands of locations contaminated with asbestos.
However, not all is doom and gloom. One of Willenbring’s fellow authors on the study — Sanjay Mohanty from UCLA’s Civil and Environmental Engineering school — explained that various forms of organic sludge affect asbestos’ movement through the soil differently.
For example, their research paper showed that natural organic matter “has the least effect on asbestos mobility,” as compared to sludges containing humic or fulvic acids.
“By identifying the [sludge] types that have the worst effect, the remediation design could exclude those organic amendments,” he noted.