Exposome and Exposure Modeling

USEtox near-field

About this project

USEtox (https://usetox.org/ ) is a scientific consensus model endorsed by the UNEP/SETAC Life Cycle Initiative for characterizing human and ecotoxicological impacts of chemicals. However, USEtox only focuses on the chemicals emitted to the far-field environment, while lacking the ability to characterize the impacts of chemicals occurring in the near-field environment, which has been found to contribute significantly to the overall human health impacts throughout a product’s life cycle. We thus developed a model based on the original USEtox model to integrate near-field chemical exposures, called “USEtox near-field”.

People

Lei Huang (huanglei@umich.edu)

Peter Fantke (pefan@dtu.dk)

Olivier Jolliet (ojolliet@umich.edu)

Keywords

USEtox, near-field exposures, consumer products, life cycle impact assessment (LCIA), matrix inversion, transfer fractions

Project Summary

The original USEtox uses a matrix of transfer rate constants (the K matrix) to characterize the transfer between compartments. In USEtox near-field, we converted these transfer rate constants to direct transfer fractions from emission to receiving compartments. To integrate near-field exposures, we added near-field compartments (e.g. product, near-person air) and collected them with far-field compartments in the original USEtox (e.g. air, water, soil) via wastewater treatment plant (WWTP) and landfill. The direct transfer fractions from the product to various near-field, far-field and human intake compartments for different product applications are calculated by 6 underlying models, including skin surface layer, object surface layer, article interior, food contact material, pesticides, and direct emissions). By inversion of the direct transfer fraction matrix, cumulative transfer fractions from the product to various human receptors are obtained, also known as product intake fractions (PiFs). If “the product” is chemical emission to the far-field environment, the PiFs become the intake factions (iFs). The PiFs or the iFs can be combined with the effect factors (EFs) to obtain the characterization factor (CFs) in units of DALY per chemical mass in the product or DALY per chemical mass emitted, respectively. The USEtox near-field model has been applied in batch mode to generate high-throughput estimates of PiFs for 8000 Tox21 chemicals, 600 chemicals in building materials, and 600 chemicals in toys.

This diagram illustrates the main components and the direct (i.e., first-order) transfer factions of USEtox near-field (from Fantke et al., 2016).

Publications

Peer-reviewed journal articles

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.

Published conference proceedings and abstracts

Jolliet, O., Fantke, P., Csiszar, S., Huang, L. 2015. Integrating near-field pathways into overall exposure to chemicals in consumer products. In Society of Environmental Toxicology and Chemistry (SETAC) North America 36th Annual Meeting. Salt Lake City, Utah.
Jolliet, O., Huang, L., Fantke, P. 2018. Integrating consumer and environmental exposure in life cycle impact assessment: Toward a consistent framework. In Society of Environmental Toxicology and Chemistry (SETAC) Europe 28th Annual Meeting. Rome, Italy.
Huang, L., Fantke, P., Jolliet, O. 2018. High-Throughput Exposure Modeling for 8000 Tox21 Chemicals in the Environment and in Consumer Products Based on a Modified USEtox Model. In ISES-ISEE 2018 Joint Annual Meeting. Ottawa, Canada.
Jolliet, O., Huang, L., Fantke, P. 2018. Stochastic modeling of human exposure to chemicals in consumer products. In ISES-ISEE 2018 Joint Annual Meeting. Ottawa, Canada.

Report abuse