April 25, 2022

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John Merrill and Elisabeth Hawley to Present on PFAS Treatment and Mitigation at ECEC22

John Merrill and Elisabeth Hawley, P.E., (California) will present on per- and polyfluoroalkyl substance (PFAS) treatment and mitigation online at the 2022 Emerging Contaminants in the Environment Conference (ECEC22) on April 27–28, 2022.

John Merrill is an 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.

Elisabeth Hawley is a Senior Consultant based in northern California with 16 years of experience advancing environmental remediation projects involving site characterization, fate and transport, remediation, strategies to achieve site closure, and litigation support services.

ECEC22 will feature traditional presentations and a poster session on the latest in emerging contaminant research, policies, and outreach in the soil, water, and air. In addition, there will be plenty of opportunities for discussion and networking with those interested in all aspects of emerging contaminants in the environment.

Geosyntec Participation

Using Lines of Evidence to Assess the Effectiveness of Innovative PFAS Treatment Technologies
Presenter: John Merrill
Time/Date: 11:45 a.m.–12:00 p.m. CST on April 27, 2022
This project developed lines of evidence, best practices, and other considerations for assessing the performance of innovative PFAS treatment technologies. The project team developed a technology evaluation checklist to evaluate three lines of evidence (1) a measured decrease in target PFAS concentrations, while quantifying or controlling for common losses and attempting to close the mass balance; (2) an identified mechanism that is consistent with previously published research and is supported by kinetic data, the detection of intermediates, control study results, or other research findings; and, (3) the detection of PFAS transformation products, including shorter-chain intermediates, fluoride, or carbon. Best practices for researchers were also identified, as well as other considerations to evaluate that could decrease the effectiveness of PFAS treatment (e.g., PFAS or co-contaminant concentrations, pH, ionic strength, temperature, or other water quality parameters). Results will guide technology developers and evaluators with clear metrics for strengthening research plans and study design, accelerating the development of promising PFAS treatment technologies, and improving the return on research investments.

Assessing and Mitigating Bias in PFAS Concentrations during Groundwater and Surface Water Sampling
Presenter: Elisabeth Hawley
Time/Date: 5:00–5:15 p.m. CST on April 28, 2022
Because fluorinated polymers are commonly used in sampling equipment and other materials and some PFAS are known to transform/degrade to form others, there is a concern that PFAS sample results can be inadvertently biased. Even low per- and polyfluoroalkyl substances (PFAS) detections may have implications for site investigation and waste disposal. Therefore, sampling guidance is often cautiously restrictive, increasing the cost and effort associated with sample collection. This presentation will summarize findings from an ongoing SERDP project, including science-based guidelines for practical field sampling equipment and procedures, sample shipping and storage, and research frontiers to improve techniques for surface water PFAS sampling (i.e., surface microlayer sampling methods to assess PFAS stratification and enrichment at the air/water interface and variability in field measurements using different common PFAS sampling methods).

More Information

About the event: ECEC22
For consultation regarding PFAS treatment and mitigation, contact John Merrill at This email address is being protected from spambots. You need JavaScript enabled to view it. or Elisabeth Hawley at This email address is being protected from spambots. You need JavaScript enabled to view it.
Learn more about John: John Merrill | LinkedIn
Learn more about Elisabeth: Elisabeth Hawley | Geosyntec Profile