RESUMO
The sources and risk factors for lead exposure to humans are relatively well recognized, yet much less is known about lead exposure risks and effects to wildlife. Here we utilized lead isotopic fingerprinting to investigate sources of elevated lead exposure to Laysan albatross (Phoebastria immutabilis) chicks in the Midway Island National Wildlife Refuge, which was established on the site of a decommissioned military base that previously had undergone lead remediation. Whole blood from chicks as well as soil and paint chips from the chicks' nests were collected from birds nesting close to (<5 m, building site) and distant from (>100 m, reference site) buildings and analyzed for lead levels and isotopic compositions using magnetic sector ICP-MS. Blood lead levels of chicks from the building site had a geometric mean of 190 microg/dL (average = 320 +/- 310 SD, range = 6.8-1400, n = 21) as compared to 4.5 microg/dL (average = 6.0 +/- 4.2 SD, range = 1.2-13, n = 15) in chicks from the reference site. Nest soil lead levels from both sites were similar and relatively low (0.05-11 microg/g) unless visibly contaminated with paint chips (building site). Isotopic analyses confirmed that leaded paint was the source of lead poisoning in these chicks and showed that the pathway of exposure was via direct ingestion of paint chips and not through contaminated soil. This study found continued risk to wildlife and possibly humans from lead hazards in a wildlife refuge established on a decommissioned military base. In addition, this study demonstrates the utility of lead isotopes to identify environmental lead hazards and exposure pathways to wildlife.