by Thomas Bustamante
Faculty Advisor: Dr. Andrew Dolby
Microplastics are defined as plastic fragments that are smaller than 5mm. These particles have become a ubiquitous water pollutant in recent years. While a substantial amount of research on their impacts on marine ecosystems has been conducted, the effect of microplastics on freshwater food webs remains poorly understood. In this study, we assessed the presence and concentrations of microplastic particles in the gizzards of the Canada Goose (Branta canadensis), Ring-necked Duck (Aythya collaris), Long-tailed Duck (Clangula hyemalis), Bufflehead Duck (Bucephala albeola), and Mallard (Anas platyrhynchos) hunted in the Piedmont and Coastal Plain of Virginia. Gizzards were bisected and had their contents removed for analysis. Collected gizzard contents underwent density separation in order to separate plastics from the sediment within gizzards. Isolated particles were then visually inspected under a dissecting microscope. Preliminary results show that with contamination taken into account, 90% of birds sampled contain microplastic fibers in their gizzards. These range in concentration from about 0.08-11.49 fibers/gram of gizzard material. All plastics were secondary fibers, meaning they originated from larger plastics that broke down over time. This provides further evidence that waterfowl not only ingest microplastics, but retain them in their digestive systems. Infrared spectroscopy was done on one fiber; it was determined to be polyethylene. As we move forward, we plan to incorporate chemical digestion and a more efficient chemical analysis in our methods. Further studies will also examine microplastic spatial distributions, as well as microplastics in the intestinal lining and lumen of these birds. This work will be able to help us understand the threat microplastics pose to organisms and ecosystems, as well as help us understand their geographic distributions.