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Multi-pathway exposure modelling of chemicals in cosmetics with application to shampoo
Citation:
Ernstoff, A., P. Fantke, S. Csiszar, A. Henderson, S. Chung, AND O. Jolliet. Multi-pathway exposure modelling of chemicals in cosmetics with application to shampoo. ENVIRONMENT INTERNATIONAL. Elsevier Science Ltd, New York, NY, 92-93(July-August):87-96, (2016).
Impact/Purpose:
This paper advances efforts to model multi-pathway exposures to chemical via product exposure. Currently, assessments of such exposures tend to be piecemeal. This paper develops a method that is consistent with high-throughput analysis, and with Life Cycle Assessment. Several EPA groups are working on related project, including the LC-HEM project (CSS 18.03), which is building a tool to assess near-field and far-field exposures in commercial products. Such analyses are critical to EPA's mission of protecting human health (EPA strategic goal #4).
Description:
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.
