Estimating mouthing exposure to chemicals in children's products

Background Existing models for estimating children's exposure to chemicals through mouthing currently depends on the availability of chemical- and material-specific experimental migration rates, only covering a few dozen chemicals. Objective This study objective is hence to develop a mouthing exposure model to predict migration into saliva, mouthing exposure, and related health risk from a wide range of chemical-material combinations in children's products. Methods We collected experimental data on chemical migration from different products into saliva for multiple substance groups and materials, identifying chemical concentration and diffusion coefficient as main properties of influence. To predict migration rates into saliva, we adapted a previously developed migration model for chemicals in food packaging materials. We also developed a regression model based on identified chemical and material properties. Results Our migration predictions correlate well with experimental data (R-2 = 0.85) and vary widely from 8 x 10(-7) to 32.7 mu g/10 cm(2)/min, with plasticizers in PVC showing the highest values. Related mouthing exposure doses vary across chemicals and materials from a median of 0.005 to 253 mu g/kg(BW)/d. Finally, we combined exposure estimates with toxicity information to yield hazard quotients and identify chemicals of concern for average and upper bound mouthing behavior scenarios. Significance The proposed model can be applied for predicting migration rates for hundreds of chemical-material combinations to support high-throughput screening.

Automated summary

This study aimed to develop a mouthing exposure model to predict migration into saliva, mouthing exposure, and related health risks for a wide range of chemical-material combinations in children's products. Experimental data on chemical migration into saliva was collected for different products, with chemical concentration and diffusion coefficient identified as main influencing properties. Migration predictions correlated well with experimental data, with a wide variation in mouthing exposure doses across different chemicals and materials.