Identification of Microplastics from the Nashua River Watershed Using Nile Red Staining

Kaitlyn Prentiss and Paulina Torres

Abstract: Microplastics are a continually problematic pollutant. Defined as plastic particles smaller than 5mm, microplastics are the result of fragmented plastic materials from single-use plastics, cosmetic microbeads, synthetic fibers, as well as textiles. These particles never fully decompose and contaminate our environments. Analysis of these particles in different environments, as they continue to be widely used, is imperative. Freshwater systems have received less research than marine counterparts, motivating the research for this study. In preliminary research, a group analyzed water samples from 14 different freshwater streams in the Nashua River watershed as well as from 20 fish from each of five streams. These fish, Eastern Blacknose Dace (Rhinichthys atratulus), are a species native to freshwater streams in the northeastern United States. Particles ranging in size from 150 microns to 5 millimeters were counted and recorded under a dissecting microscope. These preliminary results indicate that microplastics were found in both water and fish samples. In this study, a Nile red staining procedure that allows for the distinction between plastic and organic materials will be used to confirm that the observed particles are of plastic composition. Our results will be compared to the previous quantification of microplastics in our samples to improve our understanding of their presence in freshwater systems.