Multi-pathway exposure modeling of chemicals in cosmetics with application to shampoo

Abstract

We present a novel multi-pathway, mass balance based, fate and exposure model compatible with life cycle and high-throughput screening assessments of chemicals in cosmetic products. The exposures through product use as well as post-use emissions and environmental media were quantified based on the chemical mass originally applied via a product, multiplied by the product intake fractions (PiF, the fraction of a chemical in a product that is taken in by exposed persons) to yield intake rates. The average PiFs for the evaluated chemicals in shampoo ranged from 3×10(-4) up to 0.3 for rapidly absorbed ingredients. Average intake rates ranged between nano- and micrograms per kilogram bodyweight per day; the order of chemical prioritization was strongly affected by the ingredient concentration in shampoo. Dermal intake and inhalation (for 20% of the evaluated chemicals) during use dominated exposure, while the skin permeation coefficient dominated the estimated uncertainties. The fraction of chemical taken in by a shampoo user often exceeded, by orders of magnitude, the aggregated fraction taken in by the population through post-use environmental emissions. Chemicals with relatively high octanol-water partitioning and/or volatility, and low molecular weight tended to have higher use stage exposure. Chemicals with low intakes during use (<1%) and subsequent high post-use emissions, however, may yield comparable intake for a member of the general population. The presented PiF based framework offers a novel and critical advancement for life cycle assessments and high-throughput exposure screening of chemicals in cosmetic products demonstrating the importance of consistent consideration of near- and far-field multi-pathway exposures.

Model framework for integrating multiple exposure pathways to chemicals in household cleaning products

“…Alternatively, the daily volume of chemicals introduced to individual households ( Q A ) can be calculated from a typical volume of a product used for each activity multiplied by the percent chemical concentration in the product and thus can be used instead of Q when calculating iRs . We obtained the typical volume of product per use from a report published by the American Cleaning Institute and the percent chemical concentration in a product from multiple sources (see Table S10 for selected chemical composition for each product type).…”

Qualitative Approach to Comparative Exposure in Alternatives Assessment

“…This would require the use of quantitative approaches that account for these competing exposure and removal pathways (Csiszar et al , 2017Ernstoff et al 2016). Comparison of the inhalation and dermal exposure benchmarks for the 2 substances is needed to determine whether the presumed shorter exposure duration for the inhalation pathway equates to a lower risk potential.…”

“…This is especially relevant for this leave-on cosmetic case study, for which the higher skin permeation of Muscone may be at least partly compensated by its higher volatilization compared to musk xylene. This would require the use of quantitative approaches that account for these competing exposure and removal pathways (Csiszar et al , 2017Ernstoff et al 2016).…”

Modeling pharmaceutical emissions and their toxicity‐related effects in life cycle assessment (LCA): A review

“…Direct exposure of patients to pharmaceuticals may potentially be modeled by use of advancements within the USEtox model, which improved the exposure modeling to account for direct consumer exposure to chemicals encompassed in consumer products during the use phase (Fantke et al ). The adapted exposure model was applied to assess human direct exposure to chemicals contained in shampoos (Ernstoff et al ). Direct consumer exposure should be integrated into “mainstream” LCIA toxicity models to allow for better quantification of the potential human health effects from PhACs.…”