A meta-analysis to correlate lead bioavailability and bioaccessibility and predict lead bioavailability

Area of Science:

• Environmental Science
• Toxicology
• Biogeochemistry

Background:

• Accurate assessment of lead (Pb) relative bioavailability (RBA) is essential for effective remediation of contaminated sites.
• In vivo RBA measurements are reliable but labor-intensive, driving interest in high-throughput in vitro bioaccessibility (BAc) predictions.
• Heterogeneity in biomarkers, in vitro methods, and study designs complicates the correlation between in vitro BAc and in vivo RBA.

Purpose of the Study:

• To develop a robust in vivo-in vitro correlation (IVIVC) model for predicting lead (Pb) relative bioavailability (RBA) using in vitro bioaccessibility (BAc) data.
• To address and minimize heterogeneities arising from various biomarkers and in vitro approaches in existing studies.
• To estimate Pb RBA across different environmental matrices, including residential land, house dust, and mining/smelting soils.

Main Methods:

• A meta-analysis was conducted, compiling 252 paired RBA-BAc data points from nine publications.
• A Bayesian hierarchical model was employed to account for random effects and minimize study-specific variations.
• A generic linear model was established to represent the IVIVC: RBA (%) = (0.87±0.16) × BAc + (4.70±2.47).

Main Results:

• A significant IVIVC model was identified, demonstrating a strong correlation between Pb RBA and BAc.
• Differences in IVIVCs were significant across various in vitro approaches but relatively minor among different biomarkers.
• The overall estimated Pb RBA was 0.49±0.25, with higher RBA observed in residential land (0.58±0.19) compared to house dust (0.46±0.20) and mining/smelting soils (0.45±0.31).

Conclusions:

• The developed IVIVC model provides a reliable method for predicting Pb RBA from in vitro BAc data, aiding in site-specific risk assessment.
• The findings highlight the importance of considering soil type when estimating Pb RBA, with residential land showing the highest bioavailability.
• This meta-analysis offers a novel approach to correlating Pb RBA and BAc and estimating Pb RBA in diverse environmental contexts.