In a recent edition of Environment International, researchers from the University of Denmark, University of Michigan and the National Risk Management Research Laboratory in Cincinnati, Ohio, described a test method to assess one's exposure to and the fate of ingredients in cosmetic products.
According to the article abstract, the approach is a "multi-pathway, mass-balance based fate and exposure model" compatible with lifecycle and high-throughput screening assessments of cosmetic ingredients. Additional details were not provided in the abstract.
An individual's exposure from product use, post-use emissions and the environmental was quantified in vivo by measuring the original chemical mass applied via a product multiplied by the product intake fraction or PiF.
In shampoos, the average intake rate ranged from nano- to micrograms per kilogram of body weight per day, based on the levels present in the shampoo. Dermal and inhalation routes led the exposure rates. In total, the fraction of ingredients taken in by a shampoo user often exceeded, by orders of magnitude, the aggregated fraction taken in by post-use environmental emissions.
According to the authors, this PiF framework offers a "novel and critical advancement for [the] lifecycle assessment and high-throughput exposure screening" of cosmetic ingredients, and demonstrates the importance of considering multi-pathway exposures.