The state of Washington, Department of Ecology has issued an update to their environmental screening levels through their CLARC program.  This post is a summary of what is new.

What is the CLARC?

The state of Washington Department of Ecology (Ecology) Cleanup Levels and Risk Calculation (CLARC) is a table intended for cleanup site managers and other site stakeholders to determine cleanup standards, or State Actions Levels (SALs), for hazardous waste sites. On April 10, 2024, the EPA announced new National Primary Drinking Water Regulations (NPDWR) for five PFAS (per- and polyfluoroalkyl substances) chemicals: PFOA, PFOS, PFHxS, PFNA, and HFPO-DA. In response, the State of Washington Department of Ecology released a memo with updated standards to the CLARC on June 7, 2024.

What are PFAS?

Compounds known as PFAS are a family of extremely stable man-made chemicals used for making industrial and consumer products water and/or oil

Image courtesy of IMDB

resistant. Common sources of PFAS are carpeting, flooring, food packaging, outdoor equipment, electronics, automotive and aviation parts, and Aqueous Film Forming Foam, sometimes referred to as Aqueous Fire Fighting Foam (AFFF) used for containing petroleum and chemical fires. The chemicals have been used and manufactured since the 1940s and, after being extensively studied in the 1990s, were proven to be hazardous to human health. These PFAS compounds have been shown to bioaccumulate in living beings and are present in all environments studied. Since those discoveries, the EPA and Ecology have been working to publish standards regarding safe maximum concentrations of PFAS in soil and groundwater, as well as developing a cleanup procedure for sites contaminated with PFAS.

What changed in the CLARC?

Relevant changes to the CLARC include the removal of groundwater action levels for the five PFAS chemicals under column “Ground Water, Other Regulatory Criteria”, which were replaced with the EPA’s Maximum Contaminant Levels (MCLs). The EPA also released updated, non-enforceable Maximum Contaminant Level Goals (MCLGs), which were included in the CLARC update. The updated CLARC master table can be viewed publicly here.
Updated SALs (from EPA’s MCLs):
PFOA – 4 ng/kg or ppt
PFOS – 4 ng/kg or ppt
PFHxS – 10 ng/kg or ppt
PFNA – 10 ng/kg or ppt
HFPO-DA  – 10 ng/kg or ppt
EPA’s MCLGs:
PFOA – 0 ng/kg or ppt
PFOS – 0 ng/kg or ppt
PFHxS – 10 ng/kg or ppt
PFNA – 10 ng/kg or ppt
HFPO-DA – 10 ng/kg or ppt

Moving Forward

The EPA is currently investigating and researching PFAS, including detection, treatment, and remediation methods. We expect more changes to PFAS regulations are expected over the next few years as the EPA begins to enforce stricter standards around testing and abatement. At McAlister GeoScience, we are committed to staying up-to-date with the current hazardous materials and substance regulations, as well as cleanup site standards to deliver the most accurate information to our clients.
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