Publications : 2022

Dalton C, East A, Price P, Vallero D. The role of product use scheduler for estimating exposure to methyl, ethyl, propyl, and butyl parabenzoic acid (parabens) within the Combined Human Exposure Model. Poster presented at Society of Toxicology, San Diego, CA, March 2022, DOI: 10.23645/epacomptox.1934935, open access online.



Limited data are available to assess potential chemical risks to humans from manufacture, use, and disposal of consumer products and articles.  Tools are needed to access and leverage available data on chemical manufacture, use, and occurrence for important chemical exposure scenarios and pathways across the product lifecycle.  Scientific workflows are designed to execute a series of computational or data manipulation steps.  The simplest automated scientific workflows are scripts that call in data, models, and other inputs and produce outputs that may include analytical results and visualizations.  The value of using this approach is that domain-specific data types and tools can be made available to the exposure scientist and easily accessible to the exposure assessor for specific decision contexts. This product provides regulatory scientists, students and researchers with the ability to effectively access and exploit the many in silico data streams to support different regulatory purposes and supports current Agency efforts to reduce mammal study requests by 30% by 2025, and completely eliminate all mammal study requests and funding by 2035.


Paraben exposure assessments must estimate and predict doses received by persons with typical exposures and highly-exposed individuals. Exposures from product use can be significant sources of exposure for these chemicals, especially methyl ,ethyl ,propyl ,and butyl parabenzoic acid, which are used as preservatives in a wide range of consumer products including paints, dyes, arts & toys, and sealers. Because use varies across individuals and paraben levels vary in different consumer products, the general population doses vary widely. To simulate aggregate exposure to the four parabens, we input biomonitoring data into the Combined Human Exposure Model (CHEM) and compared estimates of interindividual variation in these aggregate exposures. Implementing the Product Use Scheduler (PUS) in CHEM allows researchers to assess the differences in Product Use Categories (PUCS), demonstrating the relationship between sentinel and aggregate exposures for each paraben. PUS is the CHEM module that estimates exposure from consumer products. The module accepts a spreadsheet which represents a US population and returns 364-day diaries of product use depending on the characteristics of individuals, households, and co-inhabitants. Output passed to Source-to-Dose (S2D) in CHEM, which estimates down-the-drain release and exposure. This approach provides an opportunity evaluate the applicability of a simulation model in complex product-use longitudinal exposure scenarios.