February 11, 2022

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Rula Deeb, Elisabeth Hawley, and Claire Sayler Coauthored a Report on Assessing and Mitigating Bias in PFAS Levels during Ground and Surface Water Sampling Published by SERDP/ESTCP

Rula Deeb, Ph.D., BCEEM, PMP, Elisabeth Hawley, P.E., and Claire Sayler, P.G. (California) coauthored a report entitled "Assessing the Potential for Bias in PFAS Concentrations during Groundwater and Surface Water Sampling" that was published by the Strategic Environmental Research and Development Program (SERDP)/ Environmental Security Technology Certification Program (ESTCP) on January 22, 2022.

Jennifer Field, Ph.D., Oregon State University, was the report's lead author.

Rula Deeb is a Senior Principal based in California with more than 25 years of experience focused on private practice and academia addressing the cross-media fate and transport of contaminants and the remediation of complex soil and groundwater sites impacted by non-aqueous phase liquids.

Elisabeth Hawley is a Senior Consultant based in 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.

Claire Sayler is a Project Geologist based in California experienced in hydrogeological characterization, site investigation and remediation, and litigation support. Her project management experience includes site characterization and groundwater remediation with in situ chemical oxidation, environmental consulting services to a developer constructing a large residential building in an urban area with historical groundwater contamination, and Water Supply Assessment for the permitted expansion of a gravel quarry as part of California Environmental Quality Act requirements.

ESTCP is U.S. Department of Defense's environmental technology demonstration and validation program. The Program was established in 1995 to promote the transfer of innovative technologies that have successfully established proof of concept to field or production use. ESTCP demonstrations collect cost and performance data to overcome the barriers to employ an innovative technology because of concerns regarding technical or programmatic risk, the so-called "Valley of Death."


The report evaluated the scientific basis for PFAS sampling restrictions by reviewing relevant scientific publications, evaluating several large datasets of field equipment blank results, summarizing key findings of ongoing studies under SERDP project ER19-1205, and surveying industry professionals to identify and review other available resources. Results indicate that many PFAS sampling restrictions in current guidance are not science-based but rather are based on the precautionary principle. For example, some guidance documents unnecessarily restrict the use of materials and equipment in the field that are never in direct contact with water inside sample bottles and have no credible pathway for biasing sample results (e.g., waterproof field notebooks, permanent markers, post-it notes, blue ice).

The findings presented in this document suggest that agencies who have published PFAS sampling guidance should regularly review and update their guidance based on the latest published scientific literature. Field practitioners who sample groundwater and surface water for PFAS should similarly review and update SOPs to be consistent with applicable regulatory requirements and to reflect science-based evidence, as summarized in this document. Removing restrictive specific requirements from guidance and SOPs and instead requiring field staff to take general precautions to prevent and demonstrate sample integrity (e.g., glove changes, field blanks) will reduce the effort and cost associated with PFAS sampling without compromising sample results or introducing sample bias.

More Information

Learn more about the article: ER19-1205 Project Overview (serdp-estcp.org)
Learn more about SERDP/ESTCP: Strategic Environmental Research and Development Program, Environmental Security Technology Certification Program (serdp-estcp.org)
For consultation regarding PFAS, contact Rula Deeb at This email address is being protected from spambots. You need JavaScript enabled to view it., Elisabeth Hawley at This email address is being protected from spambots. You need JavaScript enabled to view it., or Claire Sayler at This email address is being protected from spambots. You need JavaScript enabled to view it.
Learn more about Rula at: Rula Deeb | Geosyntec
Learn more about Elisabeth at: Elisabeth Hawley | Geosyntec
Learn more about Claire at: Claire Sayler | LinkedIn