Developing probability distributions for transfer efficiencies for dermal exposure.

Area of Science:

• Environmental Health
• Toxicology
• Exposure Science

Background:

• Dermal exposure models often use stochastic techniques to account for variability and uncertainty.
• Transfer efficiencies (TEs) are critical for assessing dermal exposure, representing contaminant transfer from surfaces to skin.
• Existing studies lack sufficient data to establish robust TE distributions for stochastic models.

Purpose of the Study:

• To combine data from multiple studies to create a comprehensive dataset for transfer efficiency distribution analysis.
• To identify appropriate theoretical distributions for modeling transfer efficiencies.
• To analyze differences in transfer efficiencies across various chemicals and surface types.

Main Methods:

• Conducted a literature review to identify 35 relevant studies on transfer efficiencies.
• Employed the Kruskal-Wallis test to compare data sets and assess distributional origins.
• Utilized Kolmogorov-Smirnov and chi(2)-goodness-of-fit tests to evaluate theoretical distributions.
• Developed distributions for specific chemicals (chlorpyrifos, pyrethrin I, piperonyl butoxide) on different surfaces (carpet, vinyl, foil).

Main Results:

• Identified 35 studies with diverse sampling methods, chemicals, and surface types.
• The lognormal distribution was consistently accepted across all chemical and surface combinations analyzed.
• Significant differences (P<0.001) in fitted distributions were observed across chemicals and surface types, confirmed by the Kruskal-Wallis test.

Conclusions:

• The lognormal distribution is a suitable model for transfer efficiencies in dermal exposure assessments.
• Transfer efficiencies vary significantly based on the chemical and surface type.
• Future research should focus on large-scale studies and standardized measures for transfer efficiency to improve dermal exposure modeling.