Development of Per and Polyfluoroalkyl Substances Ecological Risk-Based Screening Levels

Area of Science:

• Environmental Toxicology
• Ecological Risk Assessment
• Environmental Chemistry

Background:

• Superfund ecological risk assessments require evaluating chemical risks to threatened and endangered species.
• Screening levels for per- and polyfluoroalkyl substances (PFAS) toxicity to ecological receptors are currently lacking.
• This gap hinders accurate risk assessment for PFAS exposure in wildlife and aquatic ecosystems.

Purpose of the Study:

• To develop risk-based screening levels (RBSLs) for PFAS to address ecological risk assessment requirements.
• To establish wildlife RBSLs using surrogate receptors representing diverse threatened and endangered species.
• To derive water quality RBSLs protective of aquatic life for 23 PFAS.

Main Methods:

• Wildlife RBSLs were derived by combining published PFAS uptake and toxicity data with receptor exposure factors for surrogate species.
• Surrogate PFAS uptake data were used to calculate RBSLs for PFAS with toxicity but insufficient bioaccumulation data.
• Water quality RBSLs were developed based on literature reviews, aquatic toxicity studies, and Great Lakes Initiative methodology.

Main Results:

• NOAEL-based wildlife RBSLs for PFAS ranged from 0.013 to 340 mg/kg (soil), 0.0014 to 370 mg/kg (sediment), and 0.000075 to 1600 mg/L (surface water).
• Chronic aquatic life RBSLs for 23 PFAS ranged from 0.00022 to 3.4 mg/L.
• Screening levels for terrestrial plants and soil invertebrates ranged from 0.084 to 642 mg/kg and 1 to 50 mg/kg, respectively.

Conclusions:

• Developed PFAS RBSLs provide crucial screening tools for ecological risk assessments, particularly for threatened and endangered species.
• The derived RBSLs support the protection of diverse wildlife, terrestrial plants, soil invertebrates, and aquatic life from PFAS exposure.
• These findings enable more robust environmental protection strategies under Superfund and other regulatory frameworks.