Attributing population-scale human exposure to various source categories: merging exposure models and biomonitoring...

Area of Science:

• Environmental Chemistry
• Exposure Science
• Toxicology

Background:

• Accurate chemical exposure estimates are crucial for population health risk assessment.
• Data on chemical production, use, and release distributions are often unavailable.
• Understanding exposure pathways informs chemical prioritization for regulatory action.

Purpose of the Study:

• To evaluate the distribution of total production volumes and environmental releases for organic compounds.
• To refine population-scale exposure estimates by integrating exposure models with biomonitoring data.
• To identify sensitive input parameters for exposure models and assess emission rate likelihoods.

Main Methods:

• Utilized Bayesian approaches to update exposure models with biomonitoring data from the NHANES survey.
• Performed generalized sensitivity analysis to identify critical model parameters.
• Analyzed chemical properties, such as octanol-water partition coefficient (Kow), to determine exposure pathway contributions.

Main Results:

• Chemical properties significantly influence exposure pathway dominance.
• High Kow compounds (e.g., DEHP, PBDEs) show >80% exposure from food and dust ingestion.
• Volatile compounds (e.g., DEP, naphthalene) are primarily encountered via inhalation or dermal uptake from consumer use.

Conclusions:

• The study provides a framework for addressing data gaps in chemical exposure assessment.
• Identified key exposure routes for different chemical classes, aiding in high-throughput chemical prioritization.
• The integrated approach enhances the reliability of population-scale exposure estimates for risk management.