PFAS Forum Date Change: Now September 9-11

Ziqi (Zeke) He


Presentation Title

What’s Behind PFAS Toxicity and State-by-State Regulation

Dr. Ziqi (Zeke) He, P.E., Senior Engineer, HSW Engineering, Inc.


The occurrence of per- and polyfluoroalkyl substances (PFAS) in the environment have been

a widely-discussed topic across the United States and at all conferences over the last few

years. However, the awareness of PFAS as chemicals of emerging concern began long before

EPA’s Health Advisory Levels (HAL) were established for PFOA/PFOS in 2016. Over the last

two decades, the drinking water “guideline” levels for PFOA/PFOS have undergone

reductions by more than two orders of magnitude primarily as a result of the developing

science surrounding the toxicity of these substances. To date, multiple states have

developed their own values different from EPA’s HAL regarding PFOA/FPOS screening,

notification, response, and cleanup levels, causing uncertainties and challenges for decision

makers of impacted businesses and industries. This presentation will examine how and why

various values for PFAS guidelines or standards have been developed by EPA and individual

states. Examples presented will include the development of HAL and screening levels by EPA,

Provisional Cleanup Target Levels by Florida, and the “Reference”, “Notification” and

“Response” Levels by California. The methodology and information presented will help

stakeholders understand perception versus real risks, derive scientifically defensible

guidelines, conduct site-specific risk assessment and/or develop site-specific cleanup levels.


Ziqi (Zeke) He, Ph.D., P.E. is a Senior Engineer at HSW Engineering, Inc. with over 18 years of research and consulting experience in the area of fate and transport/transformation of persistent and emerging organic contaminants in both natural and engineered systems.  He received his BS and MS in Civil and Municipal Engineering from Xi’an University of Architecture and Technology, and his PhD in Environmental Engineering from the Ohio State University with a minor in Geological Sciences.  He gained his PFAS chemistry knowledge and treatment experiences in the early 2000s and has been tracking new research/development on PFAS toxicity and treatment technologies.  Recently, he has led PFAS investigation and treatment system design activities at several sites.  Dr. He has also been invited as a peer reviewer for frontier scientific journals and grant proposals, and is an active member of the Interstate Technology & Regulatory Council (ITRC) PFAS team focusing on guidance document writing and reviewing.