Sarah E. Morgan - PhD Candidate, Toxicology PhD Training Program
Microplastics (MPs, 1 μm < MP < 5 mm) are an emerging contaminant of concern due to their persistence and pervasiveness. Environmental MPs are a complex mixture of various plastic polymers and sorbed chemicals that have been shown to have a wide range of toxic effects across numerous species. Since exposure to unknown quantities of MPs is unavoidable for most species, it is necessary to characterize the bioactivity of MPs present in the environment as well as supplement these results with studies using reproducible laboratory synthesized plastic particle mimetics in order to characterize the health risks associated with MP exposure. My contribution to this knowledge gap is two-fold: first we are collecting water samples from the nearshore waters of Lake Ontario near Rochester, NY and analyzing the debris using novel silicon nitride nanomembranes and various in vitro toxicity endpoints, and second, we are generating various plastic particle mimetics and monitoring both sorption and bioactivity. The initial endpoints being investigated across the two approaches are cell viability, aryl hydrocarbon receptor (AhR) activity, estrogen receptor (ER) activity, and IL-6 concentration. Initial mimetics were created using various combinations of polystyrene (PS), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), bisphenol A (BPA), and atrazine which were selected for their commercial availability, potent AhR activity, well-documented ER activity, and anti-androgenic activity respectively. I hypothesize that MP-contaminant mixtures produce toxicity profiles that are unique from those of both MP and contaminant single exposures. I have found that water samples from Lake Ontario contain isolatable debris including Nile Red positive plastic particles and that this debris is not cytotoxic, but some samples have AhR activity or increased IL-6 concentration. Additionally, I have found that soaking with both TCDD, BPA, and atrazine alters PS morphology, and these changes are reflected in decreasing AhR activity with increasing time for TCDD-PS co-exposures but may not be reflected in changes in ER activity for BPA-PS co-exposures. Overall, our ongoing work highlights the need for additional research into the effects of polymer and chemical identity on the risks associated with inevitable exposure to various MP mixtures.
May 16, 2024 @ 12:00 p.m.
Medical Center | K-207 (2-6408)
Hybrid EventHost: Advisor: Lisa A. DeLouise, PhD, MPD