MICROPLASTIC CHARACTERIZATION IN THE CHESAPEAKE AND DELAWARE BAY WATERSHEDS

Microplastic pollution (operationally defined as plastic polymers smaller than 5mm in diameter) pervades natural environments, posing a significant threat to vulnerable marine ecosystems. Research indicates that 10% of the global plastic production will be deposited into the ocean, ultimately finding its way through the marine food web through trophic scale interactions. Consequently, the exposure and bioaccumulation of microplastics in marine ecosystems serve as pivotal nodes for the movement of these pollutants through natural systems. In this study, we will determine the sources and quantify the flux of microplastic pollution in two marine systems: the estuaries of the Chesapeake and Delaware Bays, both of which are severely impacted by anthropogenic sourced pollution. Water column and sediment samples were collected from 25 major streams within the watersheds of these estuaries. Plastic particles ranging between 500-50 µm were isolated from inorganic/mineral components using gravimetric methods and separated from organic matter through reaction with Fenton’s reagent. Isolated plastic compounds were quantified using scanning electron microscopy prior to classification (as either polyethylene, polypropylene, polystyrene, or polyurethane terephthalate) by Energy Dispersive X-ray spectroscopy (EDS). A subset of microplastic samples analyzed by EDS, were reanalyzed

by Fourier Transform Infrared spectroscopy (FTIR) to confirm the plastic polymer class

assignment. To determine the flux of microplastic compounds to both estuaries, plastic counts were separately converted to fluxes for each of the four polymer classes using the average monthly stream flow rates. The data generated by this study will serve as a valuable reference, contributing to a nuanced understanding of pollution dynamics in the Chesapeake and Delaware estuaries and will delineate the primary sources of microplastics within these ecosystems.