The Dermal Advanced REACH Tool (dART): A Bayesian Model for Dermal Exposure Assessment

Area of Science:

• Occupational hygiene
• Exposure modeling
• Risk assessment

Background:

• The dermal Advanced REACH Tool (dART) is a tier 2 exposure model for estimating dermal exposure to hands for liquid and solid-in-liquid products.
• dART builds on the existing ART framework, incorporating deposition, direct emission, direct contact, and contact transfer processes.

Purpose of the Study:

• To complete the methodological framework of the dART model by integrating the mechanistic model into a statistical framework.
• To present a mixed-effects model within a Bayesian framework for modeling dermal exposure rates.
• To describe between- and within-worker variability in dermal exposure.

Main Methods:

• A Bayesian mixed-effects model was used to estimate dermal exposure rates (mg min-1).
• The model incorporates a calibrated mechanistic model for central exposure estimates based on task context.
• Prior distributions for variance components were derived from literature, allowing for updates with measurement data.

Main Results:

• The dART model provides estimates of dermal exposure incorporating task-specific information and variability.
• The framework allows for the refinement of exposure estimates using actual measurement data.
• Worked examples demonstrate initial estimates and subsequent refinement through data incorporation.

Conclusions:

• The dART model offers a comprehensive statistical framework for dermal exposure assessment.
• The model effectively quantifies and accounts for variability in exposure among workers.
• dART facilitates improved risk assessment by enabling data-driven refinement of exposure predictions.