Studying permethrin exposure in flight attendants using a physiologically based pharmacokinetic model.

Area of Science:

• Toxicology
• Pharmacokinetics
• Occupational Health

Background:

• Assessing flight attendant health risks from pyrethroid insecticides is challenging due to limited exposure data and tools linking exposure to biomarkers.
• Pyrethroid insecticides, such as permethrin, are used for aircraft disinsection, raising potential exposure concerns for cabin crew.

Purpose of the Study:

• To develop and evaluate a physiologically based pharmacokinetic (PBPK) model for assessing flight attendant exposure to permethrin during aircraft disinsection.
• To link exposure routes and levels to specific biomarker data, such as urinary metabolite concentrations.

Main Methods:

• Adapted existing pyrethroid models to create a human permethrin PBPK model, parameterized with metabolic data.
• Validated the PBPK model using data from published human studies.
• Applied the model to estimate permethrin metabolite levels (3-phenoxybenzoic acid) in flight attendants exposed via residual and pre-flight spray treatments.

Main Results:

• The PBPK model accurately predicted urinary 3-phenoxybenzoic acid (3-PBA) levels following residual disinsection treatments.
• Simulations revealed that dermal exposure was dominant (83.5%) under residual treatment, while inhalation was dominant (89.7%) under pre-flight spray treatment.
• The model quantified the toxicokinetic profiles of permethrin across different exposure scenarios.

Conclusions:

• The developed PBPK model is a valuable tool for simulating permethrin toxicokinetics and assessing human exposure in flight attendants.
• This model can inform future occupational health studies and risk assessments related to aircraft disinsection practices.