Chemicals in Consumer Products

High-Throughput Assessment of Chemicals in Consumer Products

(Apdated from Huang et al., 2017)

About this project

Thousands of chemicals have been used in consumer products, yet many of which lack exposure and toxicity information to assess their potential harmful effects to humans. Thus, in this project we investigate the human exposures to chemicals in various consumer products and the resulting health impacts using high-throughput modeling approaches. We focus on multi-pathway near-field human exposures and health impacts during the use of the consumer products. The consumer products covered include building materials, cosmetics/personal care products, toys, cleaning products, and food contact products.

Sponsors

U.S. Environmental Protection Agency

American Chemistry Council

People

Lei Huang (huanglei@umich.edu)

Vy Nguyen (nguyenvy@umich.edu)

Alice Micolier (alice.micolier@u-bordeaux.fr)

Alexi Ernstoff (alexi.ernstoff@quantis-intl.com)

Susan Csiszar

Peter Fantke (pefan@dtu.dk)

Olivier Jolliet (ojolliet@umich.edu)

Keywords

Consumer products, use stage, exposure modeling, near-field exposures, high-throughput assessment, LCA, building materials, cleaning products, toys, personal care products, food contact products, Quantitative Property-Property Relationship (QPPR)

Project Summary

Defining the Product Intake Fraction

To consistently and quantitatively compare human exposure to chemicals in consumer products, we introduced the concept of product intake fraction (PiF) – 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 demonstrated the utility of the PiF and its application modalities within life cycle assessment and risk assessment contexts. The PiF 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.

Development of a coupled near-field and far-field exposure assessment framework (PiF framework)

Humans can be exposed to chemicals in consumer products through product use and environmental emissions over the product life cycle. Exposure pathways are often complex, where chemicals can transfer directly from products to humans during use or exchange between various indoor and outdoor compartments until sub-fractions reach humans. To consistently evaluate exposure pathways along product life cycles, we developed a flexible mass balance-based assessment framework structuring multimedia chemical transfers in a matrix of direct inter-compartmental transfer fractions (i.e., first-order transfer fractions). By matrix inversion, we quantified cumulative multimedia transfer fractions and exposure pathway-specific product intake fractions (PiFs). Combining PiFs with chemical mass in product yields intake estimates for use in life cycle impact assessment and chemical alternatives assessment, or daily intake doses for use in risk-based assessment and high-throughput screening. This framework, called “PiF framework” in short, constitutes a user-friendly approach to develop, compare and interpret multiple human exposure scenarios in a coupled system of near-field (‘user’ environment), far-field and human intake compartments.

This diagram illustrates the main components and workflow of the PiF framework (from Fantke et al., 2016).

Development of high-throughput suited exposure models

For certain consumer products, existing mechanically based models to assess human exposures are complex and computation-intensive, while for certain consumer products or near-field exposure pathways, suitable models are lacking to assess human exposures during the use stage. We thus develop mechanically based, yet parsimonious and high-throughput suited models to assess the chemical emissions and resulting human exposures during the use stage, for chemicals in various consumer products including building materials, cosmetics/personal care products, toys, cleaning products, and food contact products. These models can quickly predict the use-stage chemical emissions or human exposures for a large number of chemical-product combinations, which enable the high-throughput assessment of chemicals in consumer products.

Prediction of the migrated chemical mass fraction using the high-throughput food contact material model developed by our team, compared to empirical data from US FDA, where either the measured (A) or modelled diffusion coefficient was used (B) (from Ernstoff et al., 2017).

Development of quantitative property-property relationships (QPPRs)

Models we developed require the input of key parameters to predict the chemical emissions and resulting human exposures for chemicals in consumer products. Those parameters can be experimentally measured, but experiments are expensive and time-consuming. Existing correlations to estimate these key parameters often have limited applicability. Thus, we collected a large number of measured data of key model input parameters from the literature, and developed quantitative property-property relationships (QPPRs) for estimating these input parameters which are applicable for a wide range of chemical-product combinations. We have developed QPPRs to estimate the diffusion coefficient in solid materials (D), solid material-air partition coefficient (Kma), and packaging-food partition coefficient (Kpf). These QPPRs greatly facilitate the high-throughput application of our models.

Our QPPR can predict the packaging-food partition coefficient (Kpf) as a function of chemical’s octanol-water partition coefficient (Kow), food’s ethanol equivalency, packaging material type and temperature, with an R2adj of 0.93 for experimental data. Kpf is a key parameter in assessing the exposure to chemicals in food contact products. This QPPR can also be used to predict the material-water partition coefficient (Kmw) for materials other than food packaging, which is a key parameter in assessing the dermal contact exposure to chemicals in building materials, furniture, and toys (from Huang and Jolliet, 2019).

High-throughput exposure assessments of chemicals in consumer products

To perform high-throughput exposure and impact assessments, we first gathered information on unique chemical-product combinations and chemical mass in products from the literature and various databases, for building materials, cosmetics/personal care products and cleaning products. We then used the high-throughput suited models we developed to predict the chemical emissions or human exposures during the use stage (i.e., first-order transfer fractions from the consumer product to near-field compartments or human intake compartments). Next, we used the PiF framework (described above) to calculate the product intake fractions (PiFs) from these first-order transfer fractions. The chemical mass in products were combined with the PiFs to obtain the exposure doses. Finally, the exposure doses were compared with toxicity measures from experimental studies or predicted by quantitative structure-activity relationships (QSARs) to determine the health impacts of various chemicals in consumer products.

Intake doses for semi-volatile organic compounds (SVOCs) in flooring during the first 50 days of use stage. The total intake dose combining all pathways can range from 100 to 106 µg/kg-d for children. Estimated dose for DEHP (di-2-ethylhexyl phthalate, a plasticizer) amounts to 110 µg/kg-d and corresponds well to the back calculated doses from NHANES biomarkers which is 16-100 µg/kg-d.

Human health impact associated with chemical usage per person per day for the average population (1 µDALY = 31sec of healthy lifetime lost). Most contributing consumer product usages are associated with personal care products, cleaning products, home maintenance and other home products.

Publications

Peer-reviewed journal articles

  1. Huang, L. and Jolliet, O. (2019). "A quantitative structure-property relationship (QSPR) for estimating solid material‐air partition coefficients of organic compounds." Indoor Air 29(1): 79-88.
  2. Huang, L. and Jolliet, O. (2019). "A combined quantitative property-property relationship (QPPR) for estimating packaging-food and solid material-water partition coefficients of organic compounds." Science of The Total Environment 658: 493-500.
  3. Huang, L., Anastas, N., Egeghy, P., Vallero, D., Jolliet, O., Bare, J. (2019). "Integrating exposure to chemicals in building materials during use stage." The International Journal of Life Cycle Assessment 24(6): 1009-1026.
  4. Ernstoff, A.S., Fantke, P., Huang, L., Jolliet, O. (2017). "High-throughput migration modelling for estimating exposure to chemicals in food packaging in screening and prioritization tools." Food and Chemical Toxicology 109: 428-438.
  5. Huang, L., Fantke, P., Ernstoff, A.S., Jolliet, O. (2017). "A Quantitative Property-Property Relationship for the Internal Diffusion Coefficients of Organic Compounds in Solid Materials." Indoor Air 27(6): 1128-1140.
  6. Huang, L., Ernstoff, A.S., Fantke, P., Csiszar, S.A., Jolliet, O. (2017). "A review of models for near-field exposure pathways of chemicals in consumer products." Science of The Total Environment 574: 1182-1208.
  7. Csiszar, S. A., Ernstoff, A.S., Fantke, P., Jolliet, O. (2017). "Stochastic modeling of near-field exposure to parabens in personal care products." Journal of Exposure Science and Environmental Epidemiology (27): 152-159.
  8. Fantke, P., Ernstoff, A.S., Huang, L., Csiszar, S.A., Jolliet, O. (2016). "Coupled near-field and far-field exposure assessment framework for chemicals in consumer products." Environment International 94: 508-518.
  9. Huang, L. and Jolliet, O. (2016). "A parsimonious model for the release of chemicals encapsulated in products." Atmospheric Environment 127: 223-235.
  10. Ernstoff, A. S., Fantke, P., Csiszar, S.A., Henderson, A.D., Chung, S., Jolliet, O. (2016). "Multi-pathway exposure modelling of chemicals in cosmetics with application to shampoo." Environment International 92-93: 87-96.
  11. Csiszar, S. A., Ernstoff, A.S., Fantke, P., Meyer, D.E., Jolliet, O. (2016). "High-throughput exposure modeling to support prioritization of chemicals in personal care products." Chemosphere 163: 490-498.
  12. Jolliet, O., Ernstoff, A.S., Csiszar, S.A., Fantke, P. (2015). "Defining Product Intake Fraction to Quantify and Compare Exposure to Consumer Products." Environmental Science & Technology 49: 8924-8931.