A risk assessment for lead in birds

Area of Science:

• Ecotoxicology and Ecological Risk Assessment
• Environmental Toxicology
• Avian Ecology

Background:

• Traditional ecotoxicological studies often focus on single effects of pollutants.
• A holistic approach to ecological risk assessment is gaining traction.
• Problem formulation is a critical, yet often overlooked, phase in ecological risk assessment.

Purpose of the Study:

• To apply a modified environmental health risk assessment paradigm to evaluate lead (Pb) risks in birds.
• To expand the hazard identification phase to include a comprehensive target identification phase.
• To synthesize current knowledge on lead's effects on avian individuals and populations.

Main Methods:

• Conceptual risk analysis integrating laboratory and field data.
• Modified environmental health risk assessment paradigm.
• Expanded hazard identification to target identification, including receptors, endpoints, and scales.

Main Results:

• Lead impacts birds through direct mortality and indirect effects on food availability, behavior, reproduction, and recruitment.
• Lead exposure can alter prey abundance, bioaccumulate in food chains, and affect predator-prey dynamics.
• Lead exposure negatively affects clutch size, embryo/nestling survival, growth, behavior, migration, and vulnerability to stressors.

Conclusions:

• Lead poses significant risks to avian populations through various direct and indirect pathways.
• Further research is crucial to understand lead's dynamics in tissues, low-level effects, post-fledging impacts, and lab-to-wild extrapolation.
• A comprehensive target identification phase is essential for accurate ecological risk assessment of toxicants like lead.