PFAS: An Air Force Perspective by Dr. Stephen TerMaath
Dealing with contamination of any chemical in multiple media is often complex. If the contamination impacts private or public water supplies, the cleanup process involves more stakeholders, greater regulatory scrutiny, and expectation to use the best available methodologies and technologies. These situations are difficult enough, but emerging contaminants, such as PFASs, create even more concerns and an uncertain path forward. This presentation provided a brief Air Force perspective on how a responsible party can take prudent action to protect public health without being drawn into activities for the appearance of action with an uncertain end state.
Characterizing Fluorochemicals in AFFF-Contaminated Groundwater at Military Sites by Dr. Jennifer Field
Per- and polyfluoroalkyl substances (PFASs) occur in military site groundwater due to the use of aqueous film forming foams (AFFF) for training and emergency response purposes. Current efforts funded by the SERDP program, and specifically SERDP Project ER-2126, are aimed at defining the nature and extent of PFAS contamination at U.S. military sites, especially in groundwater. Groundwater contaminated by up to mg/L levels of PFASs that is then used as a drinking water source is a potential exposure pathway for humans and wildlife. Given the complexity of PFASs associated with AFFF and their breakdown in groundwater, the unique nature of PFAS chemistry and the basics of PFAS nomenclature will be presented. A primer on the basics of analyzing for the most commonly-analyzed PFASs in EPA Method 537 and those in ‘expanded lists’ will be discussed, as well as the analytical challenges to measuring PFASs that have been only recently identified due to advanced analytical techniques. Field data, acquired under the SERDP program, on the concentration and frequency of occurrence of PFASs in U.S. military groundwater as active AFFF ingredients, minor impurities, and degradation products will be presented. The practical value of utilizing state-of-the-art methods for defining the upper limit of highly fluorinated chemicals, including the total oxidizable precursor assay and total fluorine by particle-induced gamma ray emission (PIGE) spectroscopy, will be discussed. The implications of designing remedial system (e.g., GAC systems) without complete knowledge of the nature of PFAS contamination will be offered among the concluding remarks.
Understanding the Transport of Perfluorochemicals in Groundwater at AFFF-Impacted Sites by Dr. Christopher Higgins
Poly- and perfluoroalkyl substances (PFASs) are constituents in aqueous film-forming foam used to extinguish fires. Substantially elevated PFAS groundwater concentrations have been observed at firefighter protection training areas, where co-contaminants such as chlorinated solvents and fuel hydrocarbons are also commonly present. Though regulatory efforts are focused on perfluoroalkyl acids (PFAAs), polyfluorinated species (i.e., PFAA precursors)– many of which behave differently than PFAAs are potential sources of PFAAs at AFFF-impacted sites. Bench-scale research funded by SERDP into the fate and transport potential of PFASs at AFFF-impacted sites will be presented, with a particular focus on the role of PFAA precursors. These bench-scale studies include examinations of the effects of various chemical oxidants, typically employed via in situ chemical oxidation (ISCO), on PFAA fate and transport. Finally, results from a recent field investigation funded by the Air Force, will be used to validate the bench-scale studies. The field demonstration suggested significant conversion of polyfluoroalkyl chemicals to PFAAs in situ due to natural and enhanced remediation of petroleum hydrocarbons at an AFFF-impacted site.
Dr. Stephen TerMaath is the Chief of the BRAC Program Management Division in the Air Force Civil Engineer Center, Installations Directorate, San Antonio, Texas. Dr. TerMaath’s division is responsible for executing the environmental programs, as well as the real and personal property disposal for the 40 U.S. Air Force bases being closed or realigned under the authority of the Base Closure and Realignment legislation. Dr. TerMaath has extensive experience in managing and executing restoration programs, research and development, and finding solutions to unique and challenging environmental problems with over 35 years in the military, private sector, and civil service. Dr. TerMaath received both his Bachelor of Science degree with honors in Civil Engineering and his Master of Science in Environmental Health Engineering at the University of Texas. He received his Ph.D. in environmental engineering at Purdue University.
Dr. Jennifer Field is a Professor with the Department of Environmental and Molecular Toxicology at Oregon State University. She holds a Ph.D. in Geochemistry from the Colorado School of Mines and was a Postdoctoral Fellow at the Swiss Federal Institute of Aquatic Science and Technology. Dr. Field’s general research focuses on the development of quantitative analytical methods for organic micropollutants in natural and engineered systems and the application of methods for determining micropollutant fate and transport. Early in her career, she focused on field-based research to investigate the fate and transport of surfactants in groundwater and wastewater treatment systems. She participated in interdisciplinary research with hydrologists and engineers in order to develop ‘push-pull’ tracer test methods for determining in-situ rates of reductive dechlorination and anaerobic biodegradation of aromatic hydrocarbons. Dr. Field is a pioneer in the area of fluorochemical occurrence and behavior and has focused on groundwater contaminated by fire-fighting foams, municipal wastewater treatment systems, and municipal landfill leachates. She served as an editor for Water Research from 2004 to 2008, and has served as an associate editor for Environmental Science and Technology since 2008.
Dr. Christopher Higgins is an environmental chemist examining the fate of environmental contaminants in aquatic and terrestrial systems. Dr. Higgins received his Bachelor of Arts degree in Chemistry and Chemical Biology from Harvard University, and his Master of Science degree and Ph.D. in Civil and Environmental Engineering from Stanford University. Prior to his graduate work, Dr. Higgins worked for the Cadmus Group, Inc., providing policy and regulatory support to the U.S. Environmental Protection Agency. Upon finishing his Ph.D. at Stanford in 2006, Dr. Higgins became a postdoctoral fellow at the Johns Hopkins Bloomberg School of Public Health. He joined the faculty at the Colorado School of Mines as an Assistant Professor in 2009, and was promoted to Associate Professor with tenure in 2014. His research focuses on the movement of contaminants in the environment. In particular, he studies chemical fate and transport in natural and engineered systems, as well as bioaccumulation in plants and animals. Contaminants under study in his laboratory include: poly- and perfluoroalkyl substances used in stain-repellent fabrics and fire-fighting foams; nanoparticles; wastewater-derived pharmaceuticals and personal care products; trace organic chemicals in urban stormwater; and trace metals. Dr. Higgins has authored nearly 50 peer-reviewed publications to date, and his research has been supported by the National Science Foundation, the National Institutes of Health, the U.S. Environmental Protection Agency, the U.S. Department of Agriculture, the U.S. Air Force, and the U.S. Department of Defense’s Strategic Environmental Research and Development Program.