Assessment of Microplastics in the Great Plains: Comparing Densities in Water and Benthic Sediment Across Kansas

Microplastics have come to the forefront of aquatic science over the past decade. Research on microplastics has focused primarily on presence and distribution, and the overwhelming majority of studies have been conducted in marine environments. These plastic particles have the potential to leach chemicals into the surrounding aquatic environment, or into organisms that actively or passively ingest them, affecting growth, behavior, and survival. Plastics also change the physical properties of the stream, altering temperature, permeability of water through sediments, and habitat suitability. This research quantifies microplastics in the Great Plains. Surface water and sediment samples were collected at twenty-three locations from small streams, rivers, ponds, and reservoirs in Fall 2018. We reviewed a variety of sample processing techniques and chose a method that destroyed the least amount of microplastics per sample and exhibited a high rate of recovery. Samples were filtered through a 125 µm mesh sieve and thoroughly rinsed, placed into 30 mL polypropylene vials and processed in 15mL of 1N KOH for 14 days. Microplastics were detected in all samples. Data were analyzed using a two-way analysis of variance and paired t-test. Sediment samples had orders of magnitude greater microplastic densities than water column samples. The issue of microplastics is ubiquitous across aquatic environments, and we intend to build on this research with more thorough documentation of distribution and density across the Great Plains and mechanistic experimental manipulations to assess ecological impacts on stream environments and organisms.