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Chris Higgins, professor of civil and environmental engineering at Colorado School of Mines, inspects plants in a greenhouse as part of his research on PFAS bioaccumulation in plants. Data from these earlier plant uptake studies were used in a new modeling study, published Nov. 17, 2020, in the journal Environmental Science and Technology. (Colorado School of Mines)

Barrels of soil tainted with toxic PFAS “forever chemicals” sit at Schriever Space Force Base outside Colorado Springs, the tip of a literal and metaphorical mountain of contamination sprawling across nearly 200 military bases nationally. 

The Colorado School of Mines now offers a slight glimmer of hope for the bottomless pile of bad news about PFAS. 

Early next year, chemists and engineers led by the Golden university will start attacking those barrels with nine different potential methods for removing the contamination, in search of solutions for hundreds of tainted sites across the country. Even the environmental watchdogs cataloging the depressing toll of “forever chemicals” throughout the food chain say they are encouraged by the School of Mines test. 

“A methodology for effectively cleaning up contaminated soil is urgently needed due to the incredible extent of PFAS contamination across the country and the world,” said David Andrews, senior scientist for the Environmental Working Group, a leading nonprofit on PFAS issues. “These techniques all show promise.”

Mines is using a $3.5 million Department of Defense grant to manage side-by-side experiments on the Schriever base, proposed by five private companies and the University of Missouri-Kansas City. Clarkson University will manage another set of experiments for a total of nine different potential methods. 

The goal, Mines engineering professor and lead investigator Christopher Higgins said, is to find ways to break down and eliminate toxic chemicals that can last thousands of years while slowly leaking into surface and groundwater leading to neighboring communities across America. 

“It could be centuries before all of these chemicals completely leach out of the soils and sediments into the groundwater and migrate down or further away,” Higgins said. 

The Forever Problem

“Forever chemicals,” or PFAS, are an increasing toxic burden on Colorado. We’re committed to covering the public health threats, from water and croplands to the costs to clean them up.

>> Find more coverage

Some of the thousands of variants of PFAS, which have been used for decades in firefighting foam and in water-resistant coatings for everything from carpet to clothing to fast food packaging, have leached into drinking water sources in multiple Colorado communities. The problem has reached crisis levels in communities downstream from military bases that must replace their drinking water on an emergency basis, such as Fountain south of Colorado Springs. 

Dozens of Colorado communities are spending billions of dollars on new water treatment plants to meet new EPA standards lowering the allowed PFAS in consumer supplies. 

National testing has shown the ubiquitous PFAS chemicals in the bloodstreams of nearly all humans, as well as in fish at popular angling sites in Colorado and other states. 

Not all soils or contamination or tests are the same

The simultaneous testing of different researchers’ methods should last two years at Schriever, Higgins said. Schriever base officials did not return emails or phone calls seeking comment on the tests. 

At least 189 former Air Force or Air National Guard bases have confirmed PFAS contamination, according to research by Environmental Working Group, which keeps maps and databases of PFAS testing nationwide.

Seven of those are in Colorado. “Schriever AFB and Buckley Air Force Base have some of the highest detections of PFAS in Colorado,” EWG senior policy analyst Jared Hayes said.

Ten of the bases nationally show levels of contamination over 1 million parts per trillion. The EPA recently modified its recommendations on certain variants of PFAS from a guideline of 70 parts per trillion in drinking water to 4 parts per trillion. 

A state PFAS testing program, begun in 2020 and relaunched in 2022, found more than 20 Colorado communities that are far enough over the new EPA limit that they most likely need to take action, said Ron Falco, the Colorado Department of Public Health and Environment’s safe drinking water program manager. A new water treatment facility for a city can cost $100 million or more. 

Higgins and environmental advocates said the widespread PFAS problem will require a number of different technologies for effective treatment in both water and soil. Thus the advantage of comparing up to nine different techniques during the Schriever experiments.

“We expect that there will be certain technologies that work really well for some materials, and certain technologies that will not work as well,” Higgins said. 

“An effective solution needs to destroy all PFAS without causing further contamination and must be cost-effective,” Andrews said. 

One technique in the cluster of experiments involves heating the soil along with activated carbon, Higgins said. Researchers will have to make sure they’re not creating gases containing PFAS or other toxins that would produce “secondary problems,” he said. 

Another experiment involves “soil washing,” creating a slurry of the soil and introducing bubbles in a way that separates the PFAS to be treated with liquid filtering techniques. 

The Clarkson University experiments are overseen by a School of Mines graduate, Higgins said. One of the companies testing at Schriever is using a patented technique that Higgins himself helped develop.

Michael Booth is The Sun’s environment writer, and co-author of The Sun’s weekly climate and health newsletter The Temperature. He and John Ingold host the weekly SunUp podcast on The Temperature topics every Thursday. He is co-author...