A simple dermal absorption model: Derivation and application

Csiszar

et al. 2015

Environ. Sci. Technol.

There is a growing consciousness that exposure studies need to better cover near-field exposure associated with products use. To consistently and quantitatively compare human exposure to chemicals in consumer products, we introduce the concept of product intake fraction, as the fraction of a chemical within a product that is eventually taken in by the human population. This metric enables consistent comparison of exposures during consumer product use for different product-chemical combinations, exposure duration, exposure routes and pathways and for other life cycle stages. We present example applications of the product intake fraction concept, for two chemicals in two personal care products and two chemicals encapsulated in two articles, showing how intakes of these chemicals can primarily occur during product use. We demonstrate the utility of the product intake fraction and its application modalities within life cycle assessment and risk assessment contexts. The product intake fraction helps to provide a clear interface between the life cycle inventory and impact assessment phases, to identify best suited sentinel products and to calculate overall exposure to chemicals in consumer products, or back-calculate maximum allowable concentrations of substances inside products.

Section: ■ Calculation Examples and Integrationmentioning

confidence: 99%

Defining Product Intake Fraction to Quantify and Compare Exposure to Consumer Products

Jolliet

Csiszar

et al. 2015

Environ. Sci. Technol.

“…4.3-3). Although this QSPR is a commonly used model, recent reviews and evaluations 1529 of QSPR models against in vitro data found models by ten Berge (ten Berge, 2009;ten Berge, 2010) to be 1530 the best predictors of K p (Brown et al, 2016;, specifically the ten Berge 2009 model 1531 (ten Berge, 2009) (Eq. 4.3-4) and the ten Berge 2010 model (ten Berge, 2010) updating a previous model 1532…”

Section: Key Parameters and Data Availability 1209mentioning

confidence: 99%

A review of models for near-field exposure pathways of chemicals in consumer products

Huang

Science of The Total Environment

Fantke

et al. 2017

Exposure to chemicals in consumer products has been gaining increasing attention, with multiple studies showing that near-field exposures from products is high compared to far-field exposures. Regarding the numerous chemical-product combinations, there is a need for an overarching review of models able to quantify the multiple transfers of chemicals from products used near-field to humans. The present review therefore aims at an in-depth overview of modeling approaches for near-field chemical release and human exposure pathways associated with consumer products. It focuses on lower-tier, mechanistic models suitable for life cycle assessments (LCA), chemical alternative assessment (CAA) and high-throughput screening risk assessment (HTS). Chemicals in a product enter the near-field via a defined "compartment of entry", are transformed or transferred to adjacent compartments, and eventually end in a "human receptor compartment". We first focus on models of physical mass transfers from the product to 'near-field' compartments. For transfers of chemicals from article interior, adequate modeling of in-article diffusion and of partitioning between article surface and air/skin/food is key. Modeling volatilization and subsequent transfer to the outdoor is crucial for transfers of chemicals used in the inner space of appliances, on object surfaces or directly emitted to indoor air. For transfers from skin surface, models need to reflect the competition between dermal permeation, volatilization and fraction washed-off. We then focus on transfers from the 'near-field' to 'human' compartments, defined as respiratory tract, gastrointestinal tract and epidermis, for which good estimates of air concentrations, non-dietary ingestion parameters and skin permeation are essential, respectively. We critically characterize for each exposure pathway the ability of models to estimate near-field transfers and to best inform LCA, CAA and HTS, summarizing the main characteristics of the potentially best-suited models. This review identifies large knowledge gaps for several near-field pathways and suggests research needs and future directions.

“…Further investigation of aq p K 's role in the propagated results distribution can be found with SI Figures S3-4. The influence of aq p K emphasizes the importance of obtaining good quality experimental data or at least selecting the best available predictive model, i.e the QSARs by ten Berge (2009) or Robinson presented by Wilschut et al (1995). When removing variabilities in consumer behaviors and use scenarios (exposure duration, mass applied, body surface areas, indoor ventilation rates, breathing rates) the 95% CI interval was 20 reduced by 16-22% for all example chemicals but for benzyl benzoate for which only a 4% change was seen (difference between Figure 2, where all uncertainties and variabilities are accounted for, and SI Figure S5 where only uncertainties on estimated parameters are considered).…”

Section: Sensitivity Variability and Uncertaintymentioning

confidence: 99%

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

Environment International

Fantke

Csiszar

et al. 2016

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.