USEtox modeling of children's exposures to Bisphenol A (BPA) and alternatives in toys

Background
Bisphenol A (BPA) is a known endocrine disruptor, raising concerns about its presence in children's toys. Despite its well-studied health effects, there is limited research addressing aggregate exposure to BPA in toys. Moreover, hazard and exposure information on BPA alternatives on the market is scarce.

Objective
This study applies USEtox modeling to systematically evaluate young children's exposure to BPA in toys and to compare the exposure between BPA and potential alternatives.

Methods
We assessed the exposure to BPA and alternatives across representative toy archetypes and identified dominant exposure pathways and key influencing factors. We also estimated aggregate exposure for 3-6-year-olds and evaluated health risks by comparing exposure doses to toxicity benchmarks. We assumed a mass fraction of 300 ppm of BPA and alternatives across all toys.

Results
Among individual toy archetypes, the teething ring, cowboy suit, and doll resulted in the highest daily exposure dose, with the exposure dose generally decreasing with age. Direct dermal contact, mouthing, and dust ingestion were the primary exposure pathways. The estimated dose varied with the toy's material, the chemical's properties and initial mass fraction, and children's use patterns. For aggregate exposure from multiple toys used by 3-6-year-olds, bisphenol F resulted in the highest daily exposure (2.6 µg/kg/d), while bisphenol AP had the lowest (0.14 µg/kg/d). Aggregate exposure to BPA and alternatives was dominated by different pathways depending on chemical properties. We also estimated the aggregate exposure mass of BPA during early childhood (6 months to