Microplastics in the Sediment of the Platte River, Nebraska, Usa

Microplastics are a pollutant that have permeated all ecosystems on Earth. As the accumulation of microplastics increases, it is important to study where it concentrates in the environment to gain a better understanding of the impacts it may have. Microplastics are defined as small plastic particles that are less than five millimeters in size, created by the degradation of plastic debris or manufactured as small particles. Like other sediments, microplastic particles can be transported by wind, water, and ice, and concentrated in areas where other grain types accumulate. While most microplastic research focuses on marine environments, the behavior of these particles in freshwater ecosystems, specifically in river sediments, is understudied. A large majority of studies of fluvial environments are located in urbanized areas. This study focuses on the Platte River, one of the main waterways within the Mississippi-Missouri River Basin. It is a river that does not flow through areas of high population, providing insight into the level of microplastic pollution in rural locations. The goal of this study is to quantify the microplastic abundance in the fine, medium, and coarse sand size grain fractions of sediment of the Platte River throughout Nebraska. Results will provide the first quantification of microplastic concentrations of river sediments in the central United States. Sampling locations span the length of the River, including the North and South Platte, starting in Colorado and Wyoming and ending in the Missouri River. Samples are first sieved to isolate the sand size fractions. Using zinc chloride as a density floatation solution, microplastics are separated from sediments, extracted by vacuum filtering, and then quantified using a binocular microscope. Results provide insights into the level of microplastic pollution in rural settings and allow assessment of the role of the Platte River as both a sink and potential source of microplastic debris to the Missouri River.