Investigating Environmental Microplastic Particles and Pollutant Interactions in a Changing Environment

Abstract – Project 2 The objectives of Project #2 are to improve our understanding of human exposure to environmental microplastics and to learn how persistent organic pollutants (POPs) and metal ions interact with microplastics to modify toxicity. Microplastics are ubiquitous environmental pollutants. Though humans are chronically exposed to microplastics, the literature pertaining to mammalian health risks is sparse. The preponderance of literature focuses on enumerating the size, shape and color of environmental microplastics and on examining the toxicity of commercial pure plastic particles, principally polystyrene microspheres, on aquatic organisms. Studies find that microplastic toxicity increases with decreasing microplastic size, however, collecting environmental microplastic <100 ìm in diameter for testing is challenging, so it is rarely done. Recently, we showed that nanomembrane filter technology is able to filter microplastics in size ranges that are smaller than is typically feasible and is more likely to breech epithelial barriers to interact directly with cells. Furthermore, it is known that environmental microplastics adsorb POPs and/or metal pollutants, yet little is fundamentally understood about how microplastic/pollutant interactions may alter toxicity. This project seeks to remedy these knowledge gaps by enumerating the presence of microplastics <100 ìm in diameter in Lake Ontario water and in airborne Lake spray and testing the microplastic enriched in the retentate for cytotoxicity/bioactivity including aryl hydrocarbon receptor activity and endocrine disrupting properties. We will investigate microplastic interactions with POPs and metals that are abundant in Lake Ontario as a function of temperature to account for seasonal variations. The overall hypothesis of this project is that filtered debris from Lake Ontario water and airborne Lake spray will exhibit biological activity and that pollutant-MP interactions will alter bioactivity depending on MP composition and temperature.