A spatially-dynamic preliminary risk assessment of the bald eagle at the Los Alamos National Laboratory

Abstract

The Endangered Species Act of 1973 and the Record of Decision on the Dual Axis Radiographic Hydrodynamic Test Facility at the Los Alamos National Laboratory (LANL) require that the Department of Energy protect the bald eagle (Haliaeetus leucocephalus), a state and federally listed species, from stressors such as contaminants. A preliminary risk assessment of the bald eagle was performed using a custom FORTRAN code, ECORSK5, and the geographical information system. Estimated exposure doses to the eagle for radionuclide, inorganic metal, and organic contaminants were derived for varying ratios of aquatic vs. terrestrial simulated diet and compared against toxicity reference values to generate hazard indices (His). HI results indicate that no appreciable impact to the bald eagle is expected from contaminants at LANL from soil ingestion and food consumption pathways. This includes a measure of cumulative effects from multiple contaminants that assumes linear additive toxicity. Improving model realism by weighting simulated eagle foraging based on distance from potential roost sites increased the HI by 76%, but still to inconsequential levels. Information on risk by specific geographical location was generated, which can be used to manage contaminated areas, eagle habitat, facility siting, and/or facility operations in order to maintain risk from contaminants at low levels.