ASTM E3358-23a

1.1 Per- and polyfluoroalkyl substances (PFAS) are a group of over 7,000 manmade compounds consisting of polymeric chains of carbon bonded to fluorine atoms, usually with a polar functional group at the head. This guide recognizes that PFAS can be categorized as polymeric or nonpolymeric, collectively amounting to more than 4,700 Chemical Abstracts Service (CAS)-registered substances. Environmental concerns pertaining to PFAS are centered primarily on the perfluoroalkyl acids (PFAA), a subclass of per-and polyfluoroalkyl substances, which display extreme persistence and chain-length dependent bioaccumulation and adverse effects in biota.

1.2 The regulatory framework for PFAS continues to evolve, both domestically and internationally. The United States Environmental Protection Agency (EPA) is proceeding with a wide-ranging set of PFAS regulatory actions (EPA, 2021). While the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) does not currently recognize PFAS as hazardous substances, the statute does require actions to protect public health and the environment from contaminants and pollutants released to the environment. Other federal regulatory programs, such as the Safe Drinking Water Act are being used to address drinking water supplies adversely impacted by releases of PFAS. The Clean Water Act''s National Pollutant Discharge Elimination System (NPDES) permitting program is tool that both federal and state regulators are using to regulate the inflows of PFAS-impacted wastewaters at both publicly-owned treatment works (POTW) and federally-owned wastewater treatment plants and the concentration of PFAS in permitted effluent. EPA continues to add additional per-and polyfluoroalkyl substances to the list of substances reportable under the federal Toxic Release Inventory (TRI) reporting program. International efforts to address per-and polyfluoroalkyl substances include Australia''s PFAS National Environmental Management Plan, Version 2 (2020), Canada''s Prohibition of Certain Toxic Substances Regulations, (2022), the Stockholm Convention on Persistent Organic Pollutants, and the European Union''s Water Framework Directive (1).2

1.3 Hazardous waste treatment, storage, and disposal facilities (TSDF) currently operating under the Resource Conservation and Recovery Act (RCRA) via a Part B Permit may be ordered to investigate releases of PFAS under a RCRA Corrective Action order. EPA made a policy decision in the 1990s to defer many potential CERCLA enforcement actions to the RCRA Corrective Action Program (EPA, 1999). Permitted TSDFs at refineries may be subject to RCRA Corrective Action, as opposed to other regulatory programs, to address the releases of PFAS associated past and current use of aqueous film-forming foam (AFFF).

1.4 Numerous states and Tribes are using their existing regulatory programs to direct investigation, site remediation, and correction action related to releases of PFAS to soil, groundwater, and surface waters. These actions range from health advisories and guidelines to enforceable regulatory standards. Regulatory considerations include PFAS risks to both human health and ecological receptors that are protected under a broad array of federal, state, and tribal regulatory programs as well as by treaty rights.

1.5 This guide assists users in the identification of real property concerns that may be the source of PFAS releases or that may be adversely impacted by releases of PFAS. The goal of this guide is to assist managers of environmental risk in their resource allocation decision-making.

1.6 This guide does not constitute "All Appropriate Inquiries" as defined