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Evaluation of the Effects of PFAS Soil Adsorption and Transformation

Michael Eberle, Michael Edelman, Elizabeth Denly, Nidal Rabah |

TRC’s per- and polyfluoroalkyl substances (PFAS) experts published an article that summarized a bench‐scale study to evaluate the effect of divalent cations on the adsorption of PFAS onto soil particles.


The study entailed batch testing of a synthetic soil mixture under a range of Epsom salt (soluble magnesium sulfate heptahydrate) concentrations. The synthetic soil was produced using a mix of sand, silt, clay, and organic matter that then was mixed and saturated with water collected from a PFAS‐impacted water source.

The results indicate that variable concentrations of magnesium (divalent cation) had a minor effect on the sorption of perfluorooctane sulfonate with the highest sorption occurring in the strongest solution of Epsom salt. An unanticipated result of the test involved apparent biomediated transformation of polyfluorinated alkylated sulfonates (fluorotelomers or FTS) to perfluorooctanoic acid, perfluoroheptanoic acid (PFHpA), and perfluorononanoic acid. We believe this is the first time the complete transformation of 6:2 FTS to PFHpA has been observed and reported under ambient surface water‐like conditions within 6 months, a relatively short timeframe.

Elizabeth Denly

Elizabeth Denly serves as TRC’s Vice President, PFAS Initiative Leader. She is also the Quality Assurance & Chemistry Director, responsible for the creation and implementation of the Quality Management Plan and standard operating procedures (SOPs) for field sampling and documentation protocols. Ms. Denly also leads Quality Coordinator networks, which are responsible for the development and communication of quality initiatives within the organization. She is a chemist with 29 years of consulting experience encompassing field and laboratory analyses and audits, QA/QC, data validation, and consulting for regulatory agencies.

Ms. Denly is a leader in ITRC’s PFAS and TPH Risk Work Groups and in TRC’s Center of Research & Expertise (CORE) Emerging Contaminants Team and received the ITRC’s Industry Member of the Year Award in 2017. She is currently focusing on PFAS, specifically the nomenclature, chemistry, sampling procedures, QA/QC, and laboratory analytical methodologies, and has a significant role in educating clients, attorneys, and regulators about PFAS.

As a senior QA specialist at TRC, Ms. Denly is responsible for providing QA/QC oversight in support of a variety of environmental investigations and remediation programs including risk-based soil cleanups, ambient air monitoring, and human health and ecological risk assessments. In this role, she has directed the preparation of QAPPs, coordination with the laboratory, selection of the appropriate analytical methodologies to achieve the desired remedial standards, oversight and performance of the data validation process, and determination of the usability of the data and achievement of data objectives. Ms. Denly has provided this oversight under different regulatory programs.
Read more on Ms. Denly’s bio page. Please contact her at

Michael Eberle

Michael Eberle is a Technical Director within TRC in Philadelphia, Pennsylvania. Mr. Eberle is also a member of TRC’s Centers of Research & Expertise (CORE) for in‐situ remediation and treatment train optimization. Mr. Eberle has over 30 years of environmental consulting experience, including over 27 years of experience designing, troubleshooting, and managing the operation of multiphase hydrocarbon product extraction, bioventing, and in‐situ/ex-situ groundwater remediation systems. Additionally, Mr. Eberle is tasked with lending his chemistry background to understanding, characterizing, and tracking emerging chemicals under regulatory scrutiny.

Michael Edelman

Michael Edelman P.G., LRS, CPG is a project Director at TRC in Philadelphia, Pennsylvania. Mr. Edelman has over 30 years of experience in environmental consulting. He serves as vice president of the Pennsylvania Section of American Institute of Professional Geologists. His expertise includes in‐situ remediation, hydrogeological site characterization, and regulatory support. Mr. Edelman is a member of the TRC CORE Emerging Contaminants Team. Mr. Edelman has a masters degree in geochemistry from [Complete]

Nidal Rabah

Nidal Rabah, Ph.D., PE, LSRP, PMP is the Director of the Technical Development Unit and CORE at TRC in New Providence, New Jersey. He is responsible for the development of innovative technology and research and development initiatives including the CORE Emerging Contaminants and PFAS teams. Dr. Rabah has more than 30 years of professional and academic experience with focus on innovative remedial technologies, groundwater modeling, and water resources planning. He served on the ITRC Remediation Management of Complex Sites Guidance team. He has authored and co‐authored over 25 technical publications.

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