On April 25, 2019, the EPA published draft interim recommendations for screening and clean-up levels for groundwater contaminated with perfluorooctanoic acid (PFOA) and/or perfluorooctane sulfonate (PFOS). The draft recommendations apply to sites that are evaluated under federal clean-up programs, like CERCLA or RCRA.
EPA recommends a screening level of 40 parts per trillion (ppt) for PFOA and PFOS. Screening refers to the process of identifying and defining the areas, contaminants, and conditions at a site that may require further attention. It is not a cleanup level.
When PFOA and PFOS are below the screening level, generally no further action or study will be required. Even if levels are greater than 40 ppt, additional clean-up may not be necessary but further investigation will be warranted. EPA based its recommended screening level of 40 ppt on three factors:
- The specific and limited purpose of a screening level.
- The additive toxicity of PFOA and PFOS.
- The possibility that other PFAS compounds, which may be toxic but for which toxicity values may not currently be available, may be co-located with PFOA and/or PFOS.
For the first time, EPA used a drinking water health advisory to inform its recommended preliminary remediation goal (PRG). EPA based its recommended PRG of 70 ppt for contaminated groundwater that is or has the potential to be drinking water on the Lifetime Drinking Water Health Advisory of 70 ppt for PFOA and PFOS.
PRGs represent levels that EPA believes, based on the best available science and preliminary site information, are protective of human health and the environment. PRGs are based on applicable or relevant and appropriate requirements (ARAR) (e.g. maximum contaminate levels) where available. EPA recommends using the PRG of 70 ppt where state or tribal laws do not have qualifying ARARs. EPA's draft recommendations recognize that PRGs are often modified to ensure that clean-up is protective of human health and the environment.
The public may comment on the draft guidance through June 10, 2019. EPA specifically invites comment on its use of the Lifetime Drinking Water Health Advisory level of 70 ppt as the recommend PRG.