B24 – Modeling exposure and biodistribution of microplastic particles in the human body

Description

Mechanistic basis for the proposed research

A probabilistic lifetime exposure model will be provided, which accounts for intake via inhalation and a broad suite of food types, intestinal absorption, biodistribution and renal and/or biliary excretion (Figure 1). The model probabilistically simulates microplastic concentrations in the gut, body tissue (organs, biofluids) and stool. The simulated concentrations in blood, organs and stool, allow for validation against empirical data. Rescaling and alignment methods will be used to ensure comparability between microplastic
abundance data in food, drinking water and inhaled air. Ingested and absorbed MP will be modelled as a continuous distribution of particle sizes, for which bioaccessibility cut-off values will be implemented probabilistically.

Advances in relation to the current state of the science

1. External exposure modelling will include the newest concentration data for the relevant uptake pathways, and more exposure pathways will be included.
2. The model will simulate the uptake and distribution of toxicologically relevant metrics (TRM) such as particle volume, area or aspect ratio, rather than only number and/or mass concentration.
3. External exposure modelling will include the latest probability density function parameters
4. Uptake via inhalation and distribution in biofluids (e.g. blood) will use the relevant accessible volume (RAV) concept.
5. Size cut off values for transfer will be implemented probabilistically.
6. The smallest size classes, including submicron particles, we be quantified using scaling methods based on known probability density functions (PDFs) for nano- and microplastic.

This project is co-sponsored with PlasticsEurope.