Predictive framework for estimating exposure of birds to pharmaceuticals

Area of Science:

• Environmental Toxicology
• Ecotoxicology
• Pharmacokinetics in Wildlife

Background:

• Pharmaceuticals are increasingly detected in aquatic environments.
• Wildlife feeding at wastewater treatment plants (WWTPs) face potential exposure.
• Limited pharmacokinetic data for wildlife hinders ecological risk assessment.

Purpose of the Study:

• To develop and evaluate a predictive framework for estimating pharmaceutical concentrations in wildlife.
• To assess the accumulation and uptake of pharmaceuticals in wildlife food chains.
• To determine the effectiveness of a read-across approach using human or rodent data for wildlife pharmacokinetics.

Main Methods:

• A multi-step framework estimating pharmaceutical concentrations in wastewater, food items, and wildlife tissues.
• Utilizing a read-across approach with rodent and human pharmacokinetic data (absorption, distribution, metabolism, excretion).
• Comparing framework predictions against experimental data for birds exposed to fluoxetine at WWTPs.

Main Results:

• Estimated wastewater concentrations were lower than measured.
• Food concentrations were reasonably estimated with bioaccumulation data.
• Rodent-to-bird read-across performed better than human-to-bird.
• The framework adequately predicted plasma concentrations and elimination but poorly predicted tissue distribution.

Conclusions:

• The developed framework shows promise for estimating pharmaceutical exposure in wildlife.
• Improving understanding of physiological differences between birds and mammals is crucial for accurate risk assessment.
• Further research is needed to refine tissue distribution predictions in ecological risk assessments.