Background/Objectives

The objective of this panel discussion is to provide an interdisciplary, interpretive and practical discussion of the challenges associated with per- and polyfluoroalkyl substances (PFAS) fate and transport in multiple media. PFAS are manmade and ubiquitous in the environment after nearly seven decades of use and release. Local, regional, national and global detections of PFAS in different environmental media (e.g., soils, groundwater, surface waters, sediments, precipitation, air, tissues, blood serum) are evident and the literature verifies their persistence and mobility. With the advance of analytical techniques, PFAS can now be detected at subpart per trillion levels and even parts per quadrillion range. It is anticipated that the frequency of low-level PFAS detections will rise as more PFAS monitoring is requested by different regulatory agencies. The potential for intermedia transfers of PFAS between different media is an area of intense ongoing study with many significant gaps in understanding.

Approach/Activities

The issue of whether site closure is even possible for PFAS is a concern for all parties. Overall decision-making challenges exist at multiple scales from individual site management or product formulation decisions for individual PFAS compounds to societal priorities about relative environmental risks, level of risk tolerance and public policy priorities. Financial implications include concerns about product design and stewardship, remediation costs, and regulatory burdens, regardless of whether the costs are borne by the taxpayer or regulated parties. The social implications of ubiquitous PFAS occurrence and transfers between media include challenges with risk communication, public anxiety, and calls for restrictive policies.

What is the current state of knowledge about the potential for inter-media transpers for PFAS? Should all detections of PFAS in all media be considered a public health concern? Are there socio-economic patterns and environmental justice issues in perceptions of exposure to PFAS? If PFAS are present in all media, then how do we prioritize which media are of most concern and should be addressed first? Can any detections at a site suggest the presence of PFAS sources due to a particular type of source? Is it useful to differentiate site-derived impact versus ambient levels? Is the beneficial reuse of excess construction soils in jeopardy because of ubiquitous background levels of PFAS in urban areas and can land application of biosolids lead to municipal liabilities due to past and future land application of biosolids? Is compost safe to use? Can recognition of background levels of PFAS help sort out what sources of PFAS can be regulated and which cannot practically be restricted? How do and where do we draw the line to distinguish between necessary and unnecessary remediation of PFAS?

Results/Lessons Learned

This seasoned and diversified panel will provide an update on the current state of understanding, and interactive discussions on the different ways in which multi-media occurrence of PFAS are presented, perceived and interpreted by different stakeholders. Rather than a purely technical enumeration of PFAS occurrence in multiple media, the panel will discuss approaches to regulatory and public health consideration of this issue, and the practices that can be considered to provide a more rigorous and financially grounded evaluation of PFAS levels in multiple media for developing remediation goals, site decision-making and risk management strategy.