Avian toxicity reference values for perfluorooctane sulfonate.

Area of Science:

• Environmental Toxicology
• Avian Ecology
• Chemical Risk Assessment

Background:

• Perfluorooctane sulfonate (PFOS) is a persistent environmental contaminant.
• Avian predators are susceptible to the toxic effects of PFOS due to biomagnification.
• Establishing safe exposure levels is crucial for avian population health.

Purpose of the Study:

• To derive toxicity reference values (TRVs) and predicted no effect concentrations (PNECs) for PFOS.
• To assess PFOS risks for avian populations, focusing on top predators.
• To provide benchmarks for environmental monitoring and regulatory action.

Main Methods:

• Utilized data from northern bobwhite quail and mallard dietary exposures (acute and chronic).
• Incorporated toxicological endpoints including mortality, growth, reproduction, and histopathology.
• Applied US EPA Great Lakes Initiative and European Commission methodologies for TRV and PNEC derivation.

Main Results:

• Derived TRVs for PFOS dietary intake, serum, liver, and egg concentrations.
• Calculated PNECs for PFOS based on dietary, serum, liver, and egg concentrations.
• Established uncertainty factors and assessment factors specific to PFOS toxicity in birds.

Conclusions:

• The derived TRVs and PNECs are protective of avian populations under specified assumptions.
• Benchmarks provide quantitative guidance for managing PFOS risks in avian wildlife.
• This study contributes to the ecological risk assessment of PFOS in top avian predators.