November 16, 2020

EPA Recommends PFOA and PFOS Groundwater Cleanup Concentrations

Perflurooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) are synthetic fluorinated organic chemicals belonging to a group commonly referred to as per- and polyfluoroalkyl substances (PFAS). Although these two compounds are no longer made in the United States, these chemicals were manufactured in numerous industries and are resistant to metabolic and environmental degradation. Thus, these chemicals are highly persistent in the environment and bioaccumulative in humans and animals.

In December 2019, EPA provided a set of interim recommendations to address groundwater contaminated with PFOA and PFOS. [OLEM Directive No. 9283.1-47] The recommendations are for locations undergoing CERCLA or RCRA corrective action cleanups and are based on EPA’s current scientific understanding of PFOA and PFOS toxicity. EPA considers these recommendations to be interim and may revise them as new information becomes available. The interim guidance recommends the following:

Sites should be screened using a recommended groundwater screening level based on a target hazard quotient (HQ) of 0.1 for PFOA or PFOS individually, which is currently 40 ng/L (equal to 40 ppt). EPA recommends an HQ of 0.1 due to the potential additive or multiplicative toxicity of PFOA and PFOS and the possibility of other toxic chemicals being co-located with these substances. In this context, an HQ is the ratio of the potential substance exposure to the level at which no adverse non-cancer effects are expected (i.e., a reference dose) for a similar exposure period.
The PFOA and PFOS lifetime drinking water health advisories (HAs) of 70 ppt (combined or individually) should be used as the preliminary remediation goal (PRG, defined at 55 FR 8712) for groundwater that is a current or potential source of drinking water. EPA recommends the value of 70 ppt where no state or tribal maximum contaminant level (MCL) or other applicable or relevant and appropriate requirements (ARARs) are available or sufficiently protective. PRGs are typically used to set initial targets for cleanup, which can then be adjusted based on site-specific information obtained during the remedial investigation/feasibility study process. State remediation goals should also be considered if they qualify as ARARs for PFOA and PFOS.
Where groundwater is currently being used for drinking water, EPA expects responsible parties to address levels of PFOA and/or PFOS over 70 ppt.

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This document addresses issues of a general nature related to the federal RCRA regulations. Persons evaluating specific circumstances dealing with the RCRA regulations should review state and local laws and regulations, which may be more stringent than federal requirements. In addition, the assistance of a qualified professional should be enlisted to address any site-specific circumstances.