June 11, 2024

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Geosyntec Practitioners Coauthor Paper in the Journal Groundwater Monitoring & Remediation

Tom Wanzek, PhD, Elisabeth Hawley, PE, John Merrill, PE, and Rula Deeb, PhD, BCEEM, PMP, coauthored “A Multiple Lines of Evidence Approach to Demonstrate Effectiveness of PFAS Remediation Technologies.”

Their other coauthors were David Sedlak of the University of California, Berkeley, Jennifer Field of the Naval Surface Warfare Center Carderock Division, and Chris Higgins of the Colorado School of Mines. The article appeared in the April edition of the journal.

Tom is a Senior Staff Scientist based in Oregon specializing in soil characterization, ecosystem restoration, and the fate and transport of per- and polyfluoroalkyl substances (PFAS) in soil systems. He offers research and development experience on retention mechanisms of PFAS from aqueous film-forming foam (AFFF) in saturated soil systems and develops user-friendly tools to estimate soil sorptive capacity for PFAS.

Rula is a Senior Principal based in California with more than 28 years of experience in private practice and academia focused on the cross-media fate and transport of emerging contaminants, including PFAS, and the remediation of complex soil and groundwater sites impacted by nonaqueous-phase liquids.

Elisabeth is a Principal Engineer based in California with more than 16 years of experience advancing environmental remediation projects involving site characterization, fate and transport, remediation, site-closure strategies, and litigation support, focusing on emerging contaminants.

John is a Professional Engineer based in California with experience in environmental site investigation and remediation, litigation support, and applied research in collaboration with university partners. John focuses on emerging contaminants, including PFAS, 1,4-dioxane, and 1,2,3-trichloropropane.

Groundwater Monitoring & Remediation publishes papers addressing treatment technologies. It also features columns, news briefs, and equipment news. Since its inception in 1981, it has advanced the practice of groundwater monitoring and remediation by pairing innovative research with practical solutions. The journal is published by the National Ground Water Association (NGWA), which advances groundwater knowledge while supporting, connecting, and advocating for members.


Significant investments have been made to develop treatment technologies, particularly destructive approaches, for a variety of PFAS that are present in groundwater, surface water, and other environmental media. A multiple lines of evidence approach was developed to assist regulators, funding agencies, and practitioners in evaluating PFAS treatment technology performance. This article describes each of three lines of evidence that a technology is effective: (1) decrease in target PFAS concentrations is observed; (2) PFAS treatment transformation products are identified and quantified; and (3) a treatment mechanism is proposed that is consistent with previous studies and supported by data. Other considerations are also described to inform conclusions about knowledge gaps and priorities for future testing. Collectively, these lines of evidence and other considerations help communicate the complexities of PFAS treatment, strengthen research plans, standardize technology evaluator reviews, and inform realistic expectations of PFAS treatment technologies.

More Information

Read the paper: A Multiple Lines of Evidence Approach to Demonstrate Effectiveness of PFAS Remediation Technologies
Learn more about Groundwater Monitoring & Remediation
Learn more about NGWA
To learn more about PFAS remediation technologies, contact Tom at This email address is being protected from spambots. You need JavaScript enabled to view it..
Learn more about Tom: Tom Wanzek | Geosyntec
Learn more about Rula: Rula Deeb | Geosyntec
Learn more about John: John Merrill | Geosyntec
Learn more about Elisabeth: Elizabeth Hawley | Geosyntec