Lead Exposure Risk from Trash Ingestion by the Endangered California Condor (Gymnogyps californianus).

Abstract

Lead poisoning from ingestion of spent lead ammunition is one of the greatest threats to the recovery of California Condors (Gymnogyps californianus) in the wild. Trash ingestion by condors is well documented, yet the extent that trash presents a lead exposure risk is unknown. We evaluated 1,413 trash items collected from condor nest areas and nestlings in the Transverse Range of Ventura County, California, US, from 2002 to 2008, for their potential as a lead exposure risk to condors. We visually identified 71 items suspected to contain sufficient lead to be of toxicologic concern. These items were leached with weak acid and analyzed for lead. Twenty-seven of the 71 leached items (~2% of the 1,413 items) were "lead containing" based on criteria of a leachate lead concentration >1 μg/mL, with the majority of these items (22; 81% of the 27 lead items) being ammunition related (e.g., spent bullet casings and jacketed bullets). Only three of the 1,413 items collected were lead containing but were clearly not ammunition related; the other two lead-containing items were unidentified. Our results suggest that trash ingestion of nonammunition items does not pose a significant lead exposure risk to the California Condor population in California.