October 18, 2021

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Geosyntec Practitioners Participated in Webinar on Vapor Intrusion and PFAS for American Bar Association

Helen Dawson, Ph.D. (Washington, D.C.) and Dylan Eberle, Ph.D. (Massachusetts) presented the webinar titled "Recent Developments in Vapor Intrusion and Environmental Forensics" for the American Bar Association at 12 pm EDT on October 5, 2021. Travis Kline. MEM (Washington, D.C.) moderated the discussion.

Helen Dawson is a Senior Principal Civil and Environmental Consultant based in Washington, D.C. with more than 30 years of experience focused on private practice, academia, and public service. Her practice spans a wide range of technical disciplines including vapor intrusion, groundwater characterization, and contaminant fate and transport modeling related to the spread of dense non-aqueous phase liquids, chlorinated solvents, and metals in the environment.

Dylan Eberle is a Scientist based in Massachusetts focused on site characterization, emerging contaminants, litigation support, and innovative remediation technologies. His work with emerging contaminants includes working on sites impacted by per- and polyfluoroalkyl substances (PFAS) and 1,4-dioxane, along with lead authorship on publications in Chemosphere and Environmental Science and Technology.

Travis Kline is a Senior Principal Toxicologist based in Washington, D.C. with more than 25 years of experience focused on human health risk assessment and applied toxicology. A board-certified environmental toxicologist, Travis has experience in litigation support developing novel approaches and solutions to the characterization of problematic exposures. His recent focus has been on risk-driven advocacy and allocation support at large, multi-Potentially Responsible Party (PRP) Superfund sites in Oregon Washington, New York, and New Jersey.

The webinar was sponsored by the American Bar Association's Section of Environment, Energy, and Resources and was part of the larger series, "Science for Environmental Lawyers."


This webinar considers two environmental issues—vapor intrusion and PFAS—that have required more and more attention from environmental lawyers in recent years. Attendees will hear from two scientific experts with considerable experience supporting property transactions and litigation related to these problems.

First, the panel will discuss the challenges of identifying and remediating vapor intrusion pathways in buildings. Indoor air contamination often results from the migration of volatile organic compounds (VOCs) from subsurface disposals into overlying buildings, but these compounds are also common in many household products and building materials. Variability in indoor air concentrations can arise from spatial and temporal variability in subsurface concentrations, temporal variability in seasonal and daily weather conditions, variability in the location and type of subsurface vapor entry points, and variability in the quantity, location and type of household or commercial products that emit VOCs.

Second, the panel will consider the latest in environmental forensics for PFAS, the ubiquitous "forever" chemicals that state and federal authorities are moving to regulate. The panel will address methods for "fingerprinting" different PFAS compounds, potentially allowing more refined source identification and liability allocation to responsible parties. Well established forensic techniques routinely used for complex priority pollutant mixtures, such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), will be discussed. The application of these established techniques to emerging contaminants of concerns such as PFAS will be covered, as well as discussion of how the complex chemistry of PFAS has led to several novel forensic techniques unique to PFAS.

More Information

About the American Bar Association: www.americanbar.org
For consultation regarding vapor intrusion, contact Helen at This email address is being protected from spambots. You need JavaScript enabled to view it.
For consultation regarding PFAS risk characterization contact Travis Kline at This email address is being protected from spambots. You need JavaScript enabled to view it. or Dylan Eberle at This email address is being protected from spambots. You need JavaScript enabled to view it.
Learn more about Helen: Helen Dawson – Geosyntec Profile
Learn more about Dylan: Dylan Eberle – Geosyntec Profile
Learn more about Travis: Travis Kline – Geosyntec Profile