Using Metrics of Human Relevant Exposures in Risk Assessment Considerations

Environmental exposures to a myriad of chemicals are associated with adverse health effects in humans. On the other hand, single chemical in vivo and in vitro studies demonstrate causal links between the chemicals and outcomes, but such studies do not represent human exposure to environmental mixtures. We will present two approaches for including human relevant exposures in steps towards risk assessment of mixtures.

We proposed linking epidemiological association with experimental evidence, where the effect of a human-relevant reference mixture (based on a Swedish pregnancy cohort) on thyroid hormone signaling was assessed and a point of departure (PoD) was derived. Toxicokinetic models were used to compare exposures of women of reproductive age in the US population to the reference mixture using a Similar Mixture Approach (SMACH). Based on our findings, 66% of women of reproductive age in the US (roughly 38 million women) had exposures sufficiently similar to the reference mixture. For this subset, a Similar Mixture Risk Index (SMRIHI) was calculated comparing their exposures to the PoD. Women with SMRIHI > 1, an indication of concern, represent 1.1 million women of reproductive age in the US. These findings indicate that a reference mixture of chemicals identified in a Swedish cohort-and tested in an experimental model for establishment of (PoDs)-is also of health relevance in a US population.

THIS IS A HYBRID SEMINAR: LIVE IN-PERSON & VIA Panopto:
This seminar will be held in Grainger Hall room 1112.
Visit the seminar website for a link to attend virtually.
Both attendance options are free and open to all.