Research: Minerals can help mitigate PFAS in groundwater

Emerging chemicals of environmental concern in water represent a major challenge for the U.S. Army Corps of Engineers, in terms of exposure risks to humans and the environment.

The U.S. Army Engineer Research and Development Center (ERDC) is working to understand detection, fate and transport, and remediation of a group of these chemicals, generally known as per- and polyfluoroalkyl substances (PFAS).

PFAS are found in everyday consumer products — from non-stick cookware to water-resistant clothing. They are also found in certain foams, known as aqueous film forming foam, used to fight fires on military and commercial airfields. PFAS may enter the environment at sites where these chemicals are made, used or disposed of and can make their way into groundwater systems through runoff or soil seepage.

“The project’s goal is to understand how substances like activated carbon and iron can aid in immobilizing PFAS from groundwater and how altering key chemical variables, like concentration and ionic strength, will impact adsorption over time."

The Strategic Environmental Research and Development Program (SERDP) and the Environmental Security Technology Certification Program (ESTCP), funded by the Department of Defense, have a core mission to address challenges, such as PFAS, and improve environmental performance.

ERDC partnered with SERDP/ESTCP on a project to identify the best technologies to characterize, treat and manage PFAS in groundwater environments, as well as to determine how mineral-based amendments can increase the removal efficiency of natural sediments.

“The project’s goal is to understand how substances like activated carbon and iron can aid in immobilizing PFAS from groundwater and how altering key chemical variables, like concentration and ionic strength, will impact adsorption over time,” said Dr. Amanda Barker, a research chemist with ERDC’s Cold Regions Research and Engineering Laboratory. “Our work also investigates overall amendment integrity and how it might physically change once distributed in groundwater systems.”

Using amendments as a simple and rapid tool to remove PFAS from groundwater is ideal for remote locations or those where it isn’t possible to completely remove impacted soil and groundwater and destroy the PFAS.

“Removal of groundwater and soil is difficult and costly, and we’ve shown amendments may aid in reducing the risk of off-site migration, which at the very least would potentially slow down the risk to humans and the environment,” Barker said.

In a laboratory setting, Barker and her team have been able to show complete removal of select PFAS using activated carbon sourced from peat mixed with iron.

“We are very excited about our recent developments as this information will be able to directly aid other basic research programs interested in understanding how PFAS migrate in the environment,” she said.

Written by Mary Miller Morgan | U.S. Army Engineer Research and Development Center

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