983407 - Development of Soil Gas Sampling and Analysis Methods for PFAS Compounds

On-Demand

Primary Author(s)

Chris C. Lutes, MS

Principal Technologist
Jacobs
Chapel Hill, NC

Slides Document Presentation

Co-Author(s)

GB

Gwendolyn Buckley

Environmental Scientist
Jacobs
Virginia Beach, VA
Victoria Boyd, PhD

Environmental Engineer
Jacobs
RT

Robert S. Truesdale, MS

Senior Research Geologist
RTI International
Durham, NC
CH

Chase Holton
HD

Helen Dawson
HH

Heidi Hayes

Technical Director
Eurofins Air Toxics LLC
Folsom, CA
JZ

John H. Zimmerman, Jr., MS

Research Physical Scientist
US EPA ORD
Durham, NC
Alan Williams, MS

Biologist
US EPA ORD
RTP, NC
Brian Schumacher, PhD

Director Ecosystems Processes Division
US EPA Office of Research and Development
Athens, GA

Several Per and Polyfluoroalkyl substances (PFAS), including a number of fluorotelomer alcohols (FTOHs), are classified under EPA’s vapor intrusion guide for CERCLA as “volatile” and on the basis of their physical properties. While the FTOH compounds have been observed in the vapor phase during ambient air sampling in remote areas by several groups, there are no known measurements of them in soil gas. Therefore, the potential of these compounds to be transported through the “classic” vapor intrusion pathway of volatilization from groundwater, diffusion through the vadose zone and advective flow into buildings is unknown.
Methods for soil gas sampling and analysis are being developed that are based on EPA method TO-17 with a multisorbent bed and thermal desorption GC/MS/MS analysis. Initial field testing in early Spring 2021 is anticipated at multiple field sites representing a variety of geologic conditions. Field samples will be collected for the analysis of a list of approximately 10 potentially volatile PFAS compounds in groundwater, bulk soil, ambient air and soil gas at multiple depths. The target compound list includes not only FTOHs but also several perfluorinated carboxylic acid and perfluro-octanesulfonamide species that may or may not be volatile. Simultaneously laboratory method validation steps to refine desorption and separation, demonstrate recovery from sorbents, establish calibration ranges, establish detection limit, evaluate accuracy of calibration, verify storage stability and evaluate high humidity effects are underway. Initial results and plans for further testing will be included in this presentation.