California Releases Conservative Human and Environmental Screening Levels
In 2019, the California State Water Board developed an investigation approach to evaluate the presence of two Per- and Polyfluoroalkyl substances (PFAS): Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoate (PFOA). Investigation orders were issued to many commercial airports, municipal solid waste landfills, and chrome plating facilities to assess potential PFAS impacts to soil and groundwater. Shortly thereafter, similar notices were issued to hundreds of public water systems with potential PFAS issues. In the very near future (mid to late 2020), the scope will broaden to include investigations at wastewater treatment plants, oil refineries, and bulk terminals.
The Regional Water Boards are tasked with overseeing PFAS investigations and understanding potential ecological and human health consequences. On May 27, 2020, the San Francisco Bay Regional Quality Water Control Board (SFWCB) issued a Technical Memorandum which presented Interim Final Environmental Screening Levels (ESLs) for PFOS and PFOA. These ESLs quantitatively evaluate potential human health and ecological issues at contaminated sites not only within the Regional Board’s jurisdiction, but potentially across California.
The Memo provides the scientific basis for the derivation of ESLs, and provides a discussion of factors that often complicate PFAS evaluation, including laboratory analytical reporting limits, ambient levels of PFAS in the environment, and site-specific evaluation of scenarios where other PFAS compounds are present.
The Memo establishes:
- Soil ESLs for terrestrial habitat, leaching to groundwater, and direct exposure human health risk scenarios (for residents, industrial/commercial workers, and construction workers); and
- Groundwater ESLs for aquatic habitat toxicity, seafood ingestion, and direct exposure human health risk.
If you think these ESLs appear very conservative, you would be correct. In fact, current analytical detection limits actually prevent truly accurate assessment compared to some of the ESLs listed above.
As the constantly broadening scope of sites potentially requiring investigation grows, more clients will find the need to utilize these ESLs to assess their own PFAS investigation results. This is especially true for sites having potential PFAS groundwater issues along with direct (or in some cases, even indirect) migration pathways to aquatic habitats, which provide potential human health exposure risks due to seafood ingestion. The Interim Final ESLs for groundwater protective of ingestion of seafood are more protective than levels established by other states. Depending on site-specific factors, ingestion of contaminated fish may be the most sensitive human health endpoint, and may drive remediation at some contaminated sites. Ingestion of fish contaminated with PFAS is a pathway of increasing concern for multiple states. For more information about Environmental Screening Levels or PFAS in California and beyond, please contact Roux below.