MICROPLASTIC CHARACTERIZATION IN THE CHESAPEAKE AND DELAWARE BAY WATERSHEDS

Worldwide, estuarine systems have been severely impacted by the introduction of emerging contaminants. Among these pervasive contaminants are nano- and micro-plastic particles defined as plastic particles less than 5mm and 1,000nm in size, respectively. They infiltrate waterways, soils, and organisms, having demonstrable effects on physical and biological processes across a range of habitats. Due to their size, past research has found that these particles bioaccumulate in aquatic organisms via trophic scale interactions, passing unimpeded through organs and disrupting natural processes. Despite growing awareness, significant gaps remain in understanding the full extent of transportation in water systems, warranting further investigation to mitigate and manage the pollutants. Our research seeks to address this gap by quantifying, categorizing, and estimating the flux of these plastics to Chesapeake and Delaware bays. We collected water and sediment samples bi-annually from 25 streams in these watersheds, isolated plastic particles via wet peroxide oxidation and light microscopy, and analyzed them via energy-dispersive X-ray spectroscopy to classify them into four main polymer classes. Our results show that polyester makes up 97% of micro- and nano-plastic particles that migrate through these watersheds, with fluxes ranging from 13,000,000 to 38,000,000,000 particles discharged per day. These data, the first for these watersheds, will set the foundation for more effective protection of the Chesapeake and Delaware Bay ecosystems.