Lead exposure biomarkers in the Common Loon

Area of Science:

• Environmental Toxicology
• Wildlife Health
• Biomarker Development

Background:

• Lead fishing tackle poses environmental risks, impacting wildlife like Common Loons (Gavia immer) through ingestion.
• Traditional blood lead biomarkers reflect only recent exposure, limiting assessment of cumulative lead burden.
• Bone lead offers a more comprehensive measure of long-term lead exposure and its effects on wildlife and aquatic ecosystems.

Purpose of the Study:

• To compare portable X-ray fluorescence (XRF) measurements of bone lead with inductively coupled plasma mass spectrometry (ICP-MS) in Common Loon cadavers.
• To evaluate the efficacy of bone lead as a biomarker for cumulative lead exposure in loons.
• To assess the relationship between bone lead levels and geographic location (coastal vs. non-coastal).

Main Methods:

• Utilized a portable X-ray fluorescence (XRF) device to measure bone lead in 75 Common Loon cadavers, with and without overlying tissue.
• Compared XRF bone lead data with ICP-MS measurements of lead in bone, body fluid, and liver samples.
• Analyzed correlations between XRF and ICP-MS lead measurements and investigated regional differences in bone lead levels.

Main Results:

• Significant correlations were found between portable XRF bone lead measurements and ICP-MS measures of bone (R=0.88), body fluid (R=0.65), and liver lead (R=0.71).
• Higher bone lead concentrations were observed in loons from non-coastal regions.
• Bone lead levels were more predictive of lead-related mortality than liver lead levels.

Conclusions:

• Portable XRF is a viable tool for measuring bone lead in Common Loons, providing a reliable indicator of cumulative exposure.
• Bone lead serves as a more effective biomarker than blood or liver lead for assessing long-term lead exposure and its impact on loon health.
• Further research is warranted to validate these biomarkers for assessing both aquatic and loon health.