Published on JD Supra, 14 April 2025
ABSTRACT:
There are several practical considerations and lessons learned from the long history of investigations into dioxins and PCBs at contaminated sites, particularly concerning detection and measurement, exposure, and toxicity. These insights are relevant to the current challenges posed by PFAS. One of the most significant challenges is the high cost of environmental testing at commercial laboratories, which is likely unavoidable. Current analytical limitations hinder thorough characterization of PFAS in the environment. Among the thousands of PFAS substances, US EPA-approved analytical methods focus on only 29 compounds in drinking water and 40 in various environmental samples. Measuring total organic fluorine (TOF) or total adsorbable fluorine (AOF) has limited utility for characterizing PFAS, similar to past experiences with total dioxins and total PCBs and the use of screening tools like CALUX. Few commercial laboratories can accurately detect PFAS at parts-per-trillion levels. Poor analytical detection thresholds and inconsistent testing methods across jurisdictions create additional complications and can lead to disputes regarding sample integrity and contamination levels. Methodologies developed for dioxin risk assessments can guide the creation of a similar framework for PFAS, focusing on essential cancer and non-cancer endpoints, as well as exposure pathways through dermal contact, ingestion, and inhalation. Historical insights from dioxin and PCB risk assessments highlight dietary intake as a significant exposure route, a finding that almost certainly applies to PFAS as well. Additionally, the diverse chemical properties of PFAS and their persistence in the environment raise broader health concerns compared to dioxins and PCBs. This underscores the need to develop toxic equivalency factors (TEFs) for improved risk analysis. Lastly, the inconsistent quality of PFAS contamination data complicates efforts to extrapolate PFAS contamination from one location to another, hindering remediation efforts at contaminated sites.
