This presentation will provide an overview of issues to consider when conducting a human health risk assessment (HHRA) at per- and polyfluoroalkyl substance (PFAS)-impacted sites. This will include:

• Available screening values for human health and a comparison of Canadian and international guidelines;
• Exposure routes and the relative significance of oral, inhalation and dermal pathways;
• Assessing PFAS in fish, meat and produce;
• Current understanding of toxicokinetics and toxic effects;
• Risk management options; and,
• Uncertainties.

Per- and polyfluoroalkyl substance (PFAS) compounds have received a great detail of attention in recent years. Whereas strides have been made in analytic technical, advances in our knowledge of toxicity, particularly to ecological receptors, have lagged behind. Because PFAS compounds are known to bioaccumulate and biomagnify in aquatic food webs, regulatory agencies at the federal, provincial and state levels are requiring ecological risk assessments (ERAs) to evaluate risk aquatic life and upper trophic level ecological receptors that forage on aquatic life. Due to absence of a robust database on the ecotoxicity of PFAS, there is a high degree of uncertainty in ERAs. As an example, only a few studies have identified toxicity reference values (TRVs) for avian receptors, with values differing by orders of magnitude. This presentation identifies ecological benchmarks for ecological receptors, the uncertainty associated with the benchmarks, implications for interpreting ERAs, and recommendations for risk management.

Steven Jones, Senior Ecologist, GHD
Dr. Steven Jones is a population and community ecologist with over 30 years experience in the consulting industry. His areas of expertise are natural resource damage assessment; ecological risk assessment; habitat creation, enhancement, and restoration; qualitative and quantitative functional assessments of terrestrial land wetland habitats, and biostatistics. He has extensive experience in designing and implementing ecological studies for a diversity of ecosystems throughout North American. His project experience includes evaluation of impacts of remedial actions on ecological resources and incorporation of compensatory restoration into remedial designs. Steven received his B.S. in Biology from Tulane University, his M.S. in Environmental Sciences from Texas Christian University, and his Ph.D in Ecology from the University of Nebraska‑Lincoln. Prior entering the consulting industry, he was a Guyer Post‑Doctoral Research Fellow in the Department of Zoology at the University Wisconsin‑Madison. He is a member of the Society of Toxicology and Environmental Chemistry and the Ecological Society of America and is a Certified Senior Ecologist.

Perfluoroalkyl substances (known collectively as PFAS) are a group of anthropogenic fluorinated organic compounds that are highly persistent and stable in the environment. Despite their prolific use in the past, the presence of PFAS in the environment was not widely reported until the late 1990s and early 2000s, and have been detected in several different media at federal and other contaminated sites.

In general, the primary exposure pathway for humans to PFAS is through food, although the dominant pathways of exposure can vary with age, substance and dose. Assessments were recently completed of the two most characterized PFAS compounds: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) with a focus on the uptake of these compounds into terrestrial (plants, animals) and aquatic foods (fish, shellfish) through bioaccumulation, bioconcentration, biomagnification and biotransfer.

This work generated a comprehensive database of transfer factors and food concentrations for PFOA and PFOS, along with some environmental media concentration data, and demonstrated how prevalent exposure to these compounds is today. The review also highlighted several challenges associated with the measurement and assessment of PFAS that must be taken into consideration when sampling and conducting risk assessments for contaminated sites investigations.

Elliot Sigal, Senior Toxicologist and Vice President, Intrinsik Corp.
Elliot Sigal is a Senior Toxicologist and Vice President of Intrinsik Corp. He has over 25 years of experience in human health risk assessment, ecological risk assessment, toxicology, peer review, public consultation, risk communication and risk management. Elliot has overseen and contributed to hundreds of risk assessment projects for industry and government and conducted peer reviews on risk assessments in jurisdictions across Canada and the U.S. related to complex contaminated sites, mining/smelting facilities, military base closures, underground storage tanks, incinerator/waste-to-energy (WTE) emissions, landfill sites, consumer products and industrial processes. He is often called upon to provide expert advice to both industry and government, including Health Canada and the Ontario Ministry of the Environment. Since 2015, he has directed the efforts of Intrinsik’s Chemical and Consumer Products team.

Elliot obtained his B.Sc. (Honours) in Toxicology from the University of Toronto, is a EUROTOX registered toxicologist and a Qualified Person for Risk Assessment in Ontario.