Microplastic Concentrations in Gizzard Shad (dorosoma Cepedianum) and Largemouth Bass (micropterus Salmoides) from Two Drinking Water Reservoirs in the Midwestern United States.

The emergence of microplastics as a widespread contaminant in marine and freshwater environments has been cause for concern. Not only can these particles be a source of persistent organic pollutants and harmful microbial assemblages, but microplastics also have the potential to impact feeding and physiological functions of organisms. To date, most environmental and ecological studies of microplastics have focused on marine systems. Research in freshwater environments has been limited, especially with respect to ingestion across trophic levels. In this study, we explored microplastic concentrations in freshwater fish and whether these concentrations were influenced by landscape or food web characteristics. We sampled gizzard shad and largemouth bass from two drinking water reservoirs in the central Midwest that have differing shoreline land use patterns. We anticipated that the reservoir with permanent residences would have greater microplastic concentrations than the one in protected parkland. We examined whether feeding guild influenced where microplastics where concentrated within fish and whether there was evidence of trophic transfer. Our results to date indicate that microplastics concentrations are similar to those found in riverine fishes, although generally slightly higher.