Use of Site-Specific Data for Modeling Selenium Bioaccumulation by Terrestrial Animals

Area of Science:

• Environmental Science
• Ecotoxicology
• Biogeochemistry

Background:

• Selenium (Se) contamination poses risks to wildlife.
• Bioaccumulation models are crucial for assessing environmental contamination.
• Kesterson Reservoir has a history of selenium contamination.

Purpose of the Study:

• To develop and refine a bioaccumulation model for predicting selenium concentrations in terrestrial biota.
• To assess ongoing wildlife risks at Kesterson Reservoir using the developed model.
• To provide a transferable model for other selenium-contaminated sites.

Main Methods:

• Utilized extensive monitoring data (1989-2006) from Kesterson Reservoir.
• Modeled selenium concentrations in soil (water-extractable and total) to predict biota concentrations.
• Validated and calibrated the model with sequential data updates and field sampling.
• Predicted selenium levels in small mammals, bird blood, and bird eggs.

Main Results:

• The bioaccumulation model accurately predicts central tendency of selenium concentrations in biota.
• Predicted upper limits of biotic exposure were generally conservative (similar or higher than measured).
• Model performance was validated across multiple years of monitoring data.
• Variability in predictions was attributed to individual animal diets and feeding ranges.

Conclusions:

• The refined bioaccumulation model effectively predicts selenium levels in terrestrial wildlife.
• The model's transfer factors and regression equations are adaptable to other contaminated sites.
• The model aids in assessing and managing selenium risks to wildlife in contaminated ecosystems.
• Continued refinement enhances the model's accuracy and applicability for environmental risk assessment.